10-12-2010

Announcements:
We will be having our second quiz next week, test on Thursday, and a party on Friday

Today we did a single replacement reactoins lab. We had four substances: Mg(NO3)2, Cu(NO3)2, Zn(CO3)2, and Ag(NO3)2. We also had three metals: Zinc, Magnesium, and Copper. We tested all three metals reactions in all four substances. Our goal was to put in order the most reactive metal to the least reactive metal. In addition, we know that all chemical reactions between the metals and substances were to be considered single replacement reactions were one element takes another's place. We made a data table to find the most reactive. We found four single replacement chemical reactions and we solved and balanced their outcomes:
Zn+Cu(NO3)2=Zn(NO3)2+Cu
Zn+Ag(NO3)2=Zn(NO3)2+Ag
Mg+Cu(NO3)2=Mg(NO3)2+Cu
Mg+Ag(NO3)2=Mg(NO3)2=Ag
Then we concluded that Magnesium was more reactive than Zinc because it had more violent reactions with the substances. So the order was Magnesium, Zinc, and Copper.

Peteri
Chemical Reactions
Scribepost
Chem2010-2011

12/8/10

Announcements

• Quiz tomorrow on balancing
• Possibly a quiz on Friday so be ready
• Test on the last Thursday before break

What We Did In Class

Today in class we first went over the homework we had the night before, which was pages 8 and 9. If you didn't do it, you probably should. It's good practice. We asked questions about it in class and got many questions cleared up. We then basically reviewed of what we learned yesterday, and elaborated more on each subject. We went over single replacement (p. 13), double replacement (p. 14), Decompostion (p. 15), synthesis (p. 16 &17), and Combustion (p. 17).

Before I describe anything we did today for you, I want you to know 1 trick that is needed every time this happens. Whenever the elements Hydrogen, Oxygen, Nitrogen, Chlorine, Bromine, Iodine, and Florine appears alone in an equation, always put a 2 after it. This is how it is used in nature so it is needed in the writing part too. A way to remember this is HONClBrIF and sound it out.

When going over single replacement, you need to find out which elements are positive or negative ions. If there are 2 positives and 1 negative, then you switch the negative from the one positive to the other. And then of course, balance it out. For example, if you had the formula: ZnS+ O2--->_____. Zn is positive, S is negative, and O is negative. So therefore, on the other side, it would be ZnO2 +S. But then you would have to balance it. So on the right side it would be 2ZnO because on the left it says there are 2 atoms of O (O2). And since I had to change that on the right, on the left it would be 2ZnS, which means on the right I would change it to 2S.

For double replacement, you do the exact same thing as single, except there will be 2 positive ions and 2 negative ions. So you would just swap them and balance them out again.

When doing decomposition, one compound splits up into 2 different ones. For example AB---> A + B. When using elements, an example would be HgO---> Hg + O2. or MgCl2---> Mg + Cl2. Make sure to balance them at the end.

Synthesis is the exact opposite of decomposition. Just put them back together. A + B---> AB. An example using elements would be K + Cl2---> KCl. Mg + O2---> MgO. Make sure that they're balanced at the end.

Finally, we have combustion. This is when there is a carbon atom, hydrogen atom, and oxygen atom all in the same equation. The answer for every single one would be CO2 + H2O no matter what. But the hard part about this is balancing them out. The easiest and smartest way to do this is by using the CHO rules. This is the order of balancing out the equation. Carbon, Hydrogen, and Oxygen. CHO. You won't forget.

Homework:

Page 10 in your journal

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THE NEXT SCRIBER WILL BE........... VIT

Announcements

Chem thinks tomorrow.

HomeWork

NONE

Body

In class today we started our new unit that has to do with Atom counting and balancing atomic equations. First is Atomic counting, it is something that we did in the begging of the year if you have an equation with 2c + 2H2 you draw two seperate C's and draw two H's together and have two of those. We also learned atomic counting, a couple examples of this are
1. 3 N2O + N2 N: 8 O: 3
2. 5 Ca(NO3)2 + 2 O2 Ca: 5 N: 10 O: 34
3. 5 C3H8O + 3 CO2 C:18 H:40 O: 11
The first number tells you how many molecules there are, the next number tells you how many of that type of atom are in that molecule. So you do the math from there.
The last thing we learned is balancing atomic equations. For example: 4 Li + 02-------2 Li20, you first find how much of each atom is in the both sides of the equation to see if there even, so in the equation above, there is 4 Li on the left side and 4 on the right, there is 2 O on the left and 2 O on the right, so this equation is right already you just have to show how you counted them. There are equations where you must show work: example: Al + Pb(NO3)2----- Al(NO3)3 + Pb, so your first step is to see how many Al are on each side, which they are equal.. so then you take the next atom which is Pb, that is equal.. so then you take the next atom which is NO3 and they are not the same, so you have to multiply the right side by 2 and the left by three, which makes it uneven again because the left side has 3Pb now so you have to multiply the left sides Pb by 3, and it is still uneven because the right side had 2 Al so you have to multiply the left sides Al by 2.. so your final equation is... 2Al + 3Pb(NO3)3----- 2Al(NO3)3 + 3Pb. And that is how you do balancing... you can do extra work on pg. 8 and 9

the next scriber will be..... Robert Maxwell Cohen.

11/22/2010

Announcements- Lab Test tomorrow.

Homework- Do the analysis questions from today's lab. Look over your labs to study for the test.

In class today we did the Polarity Olympics lab.

-Part one- Solubility.

In this part of the lab, we want to see if hexane, ethanol, pentanol, methanol, butanol, and acetone mix with water.

~This is what it looks like if it does not mix with water. There is a split between the different solutions.

After we do this, We see if it mixes immediately. If it does not mix we have to put a stopper on the test tube, shake it, and then see if it mixes then.

-Hexane- Does not mix immediately, Does not mix after shaking.

-Ethanol- mixes immediately, It stays mixed after shaking.

-Pentanol- Does not mix immediately, Does mix after shaking.

-Methanol- Does not mix immediately, Does mix after shaking.

-Butanol- Does not mix immediately, Does mix after shaking.

-Acetone- mixes immediately, Stays mixed after shaking.

-Part two- Volatility and Surface Tension

In this part of the lab we want to see which solution spreads faster and which solution evaporates the fastest. What we do is we put a drop of each liquid on the lab table and see which one spreads more and which one evaporates faster. 7th being spreads out the least and evaporates the slowest.

Liquid Spreading rank Evaporating rank

-water 7 7

-hexane 1 2

-ethanol 5 4

-pentanol 6 3

-methanol 4 5

-butanol 3 6

-acetone 2 1

The liquids that spread out more are non polar and the liquids that spread out the least are polar because the atrraction is has on the solution gets the solution closer together and holds it together more. Also if something is more polar, then it will evaporate the slowest because sticks more together to the table. That is why hexane evaporates faster, it is because it is non polar and there is no attraction to it that holds it down and together.

The next scriber will be Mahak =]

11/18/10

Announcements: Chem day tomorrow 11/19/10 in the lyceum

Quiz on Monday

Lab test on Tuesday

Homework: None

In the beginning of class we learned about polar and non-polar molecules. Polar molecules can not be split while non-polar can. If the molecule is bent it will always be polar. Just because it has polar bond does not mean it is a polar molecule.

The Lab: In the lab we put drops of water and hexane on a penny. The penny was able to hold more drops of water than hexane because it is a polar molecule. Polar molecules like to clump together because of the opposite charges within itself attract each other.

We also put drops of water and hexane in a watch glass and then put a thin glass tube (called a capillary tube) upright and covered the top of the tube so the liquids would go up the tube. The water went up further and stayed in the same spot when we tipped the tube back and forth. While the hexane didn't go up as far and would move around when tilted. Since the water molecule stayed in the same spot, the glass molecules are polar. This is because it attracted the water which is polar and did not attract the hexane because it it non-polar and likes attract likes.

In the last part of the lab we drew two lines on a watch glass. One of the lines was with a transparency marker and the other with a permanent marker. When we use the cotton swab with water on it the transparency line came off and the color leaked onto the swab. It also cleaned up all of the permanent line. Then we drew two more lines on a watch glass and put hexane on a different cotton swab. When we wiped the transparency line it did not come off and the line stayed on the watch glass. When we wiped the swab on the permanent line it came off. The ink in transparency marker is polar because the water(polar) was able to be wipe up while the hexane(non-polar) was not able to pick up the transparency line.

The next scriber will be Elizabeth.

11.16.10

ANNOUNCEMENTS: We took a quiz today, pick up pages 21-24 if you were not here, and I think that is it.

HOMEWORK: Page 24

Today we learned about different types of bonds that are related to electronegativity. Electronegativity as you may remember, describes an element's tendency to "hog" electrons (pull them closer to themselves than the other atom). We got a periodic table that has each element's electronegativity.

The three different bonds we learned were:

Purely covalent/non-polar: In this bond, neither atom has that much of a stronger pull than the other. The difference between the electronegativites of the two atoms will be 0.0-0.4

(*To find the electronegativity difference just subtract the smaller electronegativity from the larger one. EX: Carbon has an electroneg. of 2.5, Hydgrogen has an electroneg. of 2.1 so the difference is .4 This would be a non-polar covalent bond.)

Polar covalent: One atom has a slightly larger electroneg. causing it to have a stronger attraction to more electrons. Difference of electroneg. is 0.5-1.6

(EX: Hydrogen is 2.1, Oxygen is 3.5. The difference is 1.4 so it is polar covalent.)

In both of these, electrons are shared.

Ionic: In an ionic bond, one atom has a significantly larger attraction to the electrons than the other. In this case electrons are transferred. The range for this is 1.7 or greater.

(EX: Sodium is .9 and Flourine is 4.0 The difference is 3.1 so it is ionic)

We also learned how to identify atoms with a partial positive and a partial negative charge.

The atom with the greater electronegativity will have a partial negative charge because there are more electrons going towards it. And the partial positive atom has the smaller electronegativity because there are less electrons attracted to it.

Mr. Paek taught us the symbol that is used for this.

Disregard the second picture, he did not teach us that. The S looking thing is the symbol. If it's partial negative then a - sign will follow the symbol. And if its partial positive then it will be a + sign. In this image, hydrogen has an electronegativity of 2.1 and flourine has one of 4.0 Because flourine's electroneg. is greater, more electrons are attracted to it so it has a partial negative charge.

That's all folks!

Oh and the next scriber shall be Jillian (:

Monday, November15, 2010

11/15/2010

Announcements:

-Test will be on Wednesday after thanksgiving break.

-Web assigns are due Tuesday after thanksgiving break.

-Mr. Paek said he will not return our quizzes, but we get to retake one and drop the lowest.

-Mr. Paek also said that if there is anyone who doesn't get the lewis structure, they should go see him ASAP because it's important. The lewis structure is a key concept and you have to completely get it in order to understand upcoming lessons.

Homework:

-Finish up to page 19.

- Make sure you finish the 2 practice sheets we got on Thursday that go along with the chem think.(they might be collected tomorrow.)

In Class:

Well first Mr. Paek introduced to us the concept of VSEPR. He said that he will use this term a lot and he wants us to understand it. here is what each letter stand for:

-V= Valence

-S= Shell

-E= Electron

-P= Pair

-R= Repulsion

-This theory is used to prove that electron want to repel as far away from each other as possible.

-there are 5 types of molecular shapes: linear, bent, trigonal planar, trigonal pyramid, tetrahedral.

*Linear and bent are usually associated with 2 electrons and are are usually 2 dimensioned . (example by Mr. paek: If Mac and Kevin were to have a fight where would they go in the room to be as far away from each other as possible? the answer was in the corners of the room.)

*Trigonal planar, trigonal pyramid, and tetrahedral are associated with 3 electrons and are usually 3 dimensioned.(example by Mr. paek: if Max, Kevin, and Jimmy were to fight over kinga, where would they want to be in the room in order to be as far away from each other as possible? the answer was 2 would be in each corner and one would be in the middle)

- those were examples to help us visualize and help us understand what molecular shapes look like.

-Other key things to remember is that the lone pairs are key because they push everything down and change shape. And for shape you don't need dots unlike lewis structure.

- The picture at the right is page 16: I am going to go over the first one, so you guys get an idea on what we did today.

CS2

Needs: 24; Has:16;Shares:8; Bonds:4 .

I am sure we all know how to draw the lewis structure for this one ( see Mr. Paek if you don't), well the molecular shape is the same as the lewis structure but without the dots. and the name of the shape is linear.

The next scriber will be Andrea.

11-10-10 11-14-10

THURSDAY

Announcements: total review. don't forget you can drop your lowest quiz that we take.

Homework: none!!

Class: On Thursday we had a total review day. we reviewed all lewis structures, also went over homework pages 11,12,13. Then we took a quiz. after the quiz, we finished all the pages in our notebook.(up to 15) we worked on the pages all through class. most people had 10 minutes to spare at the end.

FRIDAY

Announcements:You can drop one quiz.

Homework: Finish chem think(if not finished in class) and finish the 2 practice pages.

Class: In class on Friday we went to the computer lab to work on chem thinks. The name of the chem think is "Molecular Shapes". This can be found under Covalent Bonding. It started of by explaining what VSEPR stands for. VSEPR stands for Valence Shell Electron Pair Repulsion. When you get atoms in a molecule, the bonds in the electrons repel each other. when more are added the atoms repel so they can get the furthest away from the other atoms.

While working on this chem think we had to answer a work sheet. A covalent bond is electrons being shared by two atoms. Electrons are found in the middle of the two atoms when in a covalent bond. When two atoms are bonded to a central atom the angle between them is a 180 degrees. when there are 3 is is 120 degrees. for four atoms bonded to a central atom it is 109.5 degrees.

While working with molecular shapes there are (as you can tell in the title) many different shapes. when there is just two to a bond the shape is linear. when it is in two dimensional with three atoms it is called trigonal planar. If their is a lone pair of electrons, it doesn't affect the atom but it does make the atom bent. the shape is called bent. when their is three atoms and it is three dimensional the shape is called a tetrahedral. again with lone electrons and three atoms the shape is called a trigonal pyramid.

after we finished the tutorial we moved on to the question set where you have to answer ten correct with getting 2 or less wrong. if you get three wrong you have to start over again.

Next scriber will be...... YASSINE!! (you know why)

11.9.2010

Announcements:

-During Unit 5, we will take 6 quizzes and be able to drop the lowest score.

-We took quiz #1 today.

-We will take quiz #2 tomorrow.

-We received pages 9-15 today.

Homework: Finish pages 9-15

Class: Today, we started off by doing a quick question and answer about what material was going to be on the quiz. After this, we then took our first quiz of unit 5. Once everyone had finished the quiz, Mr. Paek showed us what the answers were and went over them with us. The quiz was out of 8 total points with each question being worth half of a point.

We then started going over pages 9-15.

Page 9: This first page was Guidelines for Drawing Lewis Structures. What you first must do when you are drawing the Lewis Structures is to count the total number of valence electrons in the compound. If you are finding the structure of an ion, remember to add electrons for a negative charge and subtract electrons for a positive charge. Secondly, you should predict the arrangement of the atoms in the molecule, drawing a line to represent a single bond between each pair of bonded electrons. Thirdly, you should find the number of valence electrons left over after forming single bonds. The fourth step is to place electrons around the outside atoms until each is surrounded by eight electrons (the octet rule). H is the only element which does not follow the octet rule. The final step is to place any left over electrons around the central atom.

Page 10: Lewis Structures 1

-Ex: What is the Lewis Structure for CH4

Ans: What you would do would be to find out the needed electrons, how many electrons the compound has, how many electrons are shared, and how many bonds there are. In this instance there are 8 electrons needed for C. There are also 8 electrons needed for H4 because H needs 2 electrons and since there are 4 of the H electrons that makes 8. If you add 8+8 you will get 16. Therefore this compound needs 16 atoms. Next, is the amount of electrons they have. H4 has 4 electrons combined, and C has 4 electrons. That gives you 8 more electrons for 16. Therefore, they have 8 electrons shared. Then, you divided the shared electrons by 2 and you get the amount of chemical bonds. Then you need the formula. For this atom the formula would be H

/

H-C -H

/

H

Page 11: This is just a page of practice problems

Ex: H2O

Ans: There are 12 electrons needed, there are 8 electrons between H2 and O. There are 4 electrons shared. There are 2 bonds. Based upon this information, the formula would look like this ..

H-O-H

..

Page 12: Lewis Structures 2

Ex: Which elements are allowed to break the octet rule?

Ans: Elements allowed to break the octet rule if they do not have a full shell of valence electrons.

Ex #2: Does element A violate the octet rule?

/ / /

A

/ / /

Ans: Yes because each of those lines has two electrons in it and A would have more than eight electrons with those connected to it.

Page 13: More practice formula pages

Ex: What is the Lewis Structure for HCN?

Ans: There are 18 electrons needed, they have 10 electrons combined, therefore there are 8 electrons shared which means that there are 4 bonds. The formula would look like this:

H=C=N

Page 14: Lewis Structure 3

Ex: Draw the Lewis structures for carbon tetra-fluoride.

Ans: First you have to realize that that is CF4. Once you have done this, you can solve. Together they need 40 electrons. They have 20 electrons, this means that they share 20 electrons which comes out to 10 bonds. The formula would look like this:

.. ..

F F

/ /

C

/ /

F F

.. ..

Page 15: This is the final page of the journal and it is half of a page of practice problems.

Ex: Name the group of elements that X would belong to.

X .

Ans: X would belong to the Alkali metals group because it only has one valence electron and alkali metals only have one valence electron.

NEXT SCRIBER: JIMMY

11.8.10

Announcements:

-We picked up and taped in our calender for Unit 5

-As well as sheets 2-8

-This unit we will have 6 quizzes (and drop the lowest score if desired)

-Our first quiz will be tomorrow (Tuesday October 9, 2010)

Homework: Finish pages 2-8 (excluding page 3)

We started off by reviewing a little bit of covalent bonding (talking about where there is the least potential energy (when they are sharing electrons at a comfortable distance) and the most potential energy (when the atoms become too close so the protons of each nuclei repel each other)).

We took the rest of class to finish pages 2-8

Page 2: Questions about potential energy

-Ex: Does the potential energy increase/decrease as the atoms move closer?

Ans: Decrease as the atoms are sharing the electrons thus making their pull on them less.

Page 4: Naming Covalent Bonds Practice 1

-Ex: What is the name for the bond of CO?

Ans: Carbon Monoxide. Because there is only one carbon atom and it is the first atom named, the mono- is dropped leaving just carbon but because the second atom is oxygen and there is only one it uses the prefix mono and because the second atom should end in -ide, it becomes oxide creating Carbon Monoxide.

Page 5: Naming Covalent Bonds (2)

-Ex: CO. Ionic or Covalent?

Ans: Covalent (because it is between two non-metals) Carbon Monoxide

Page 6: Naming Covalent Bonds (3)

-Ex: Nitrogen Dioxide. Ionic or Covalent?

Ans: . NO2 (Because there is only one nitrogen it is simply nitrogen, and because there are two oxygens the prefix di- (indicating two) is placed in front of oxygen and the suffix -ide is placed at the end) and it is covalent (two non-metals)

Page 7: Naming Covalent Practice (3)

-Ex: PCl3

Ans: Phosphorous Trichloride (one phosphorous is simply phosphorous and because there are three Chlorines the prefix tri- (indicating three) is added as well as the suffix -ide)

Page 8: Naming Covalent Compounds (4)

-Ex: SiO2

Ans: Silicon Dioxide (again, one silicon is just silicon and because there are two oxygens a di- is placed in front and you get Silicon Dioxide)

8.1 - 8.2 Molecular Compounds/ Covalent Bonding

Covalent bonds are formed when electrons have a "tug of war" with each other attracting them to each other. The atom is held by sharing electrons forming a Covalent bond. The Octet Rule applies for all Covalent bonding. In the bond, electrons are trying to get the electron configuration of noble gases like Ionic bonding. For a hydrogen pair, they share the two electrons to form a hydrogen molecule. Combinations in the non-metalic elements tend to form covalent bonds. Single Covalent bonds are held by the sharing of a pair of electrons. Such as H (hydrogen atom) + another H = the single covalent bond of H:H. In "H:H", the ":" represents the shaired pair of electrons. A structural formula represents the bond using "-". For example, Fluorine has 7 valence electrons. If F+F, they still need to fill in the noble gas. so either they form together making a 14 valence electron bond, or split 7 valence electrons each. In a bond, the elements need to share valence electrons evenly with each other, thus making a covalent bond.

Chapter 8 Summary

In the last chapter, we learned about how ionic compounds connected with other molecules, and by doing this, there was a complete transfer or electrons. Each atom had its own electron, while in a covalent bond, there is a sharing of electrons which are held together. To make a covalent bond, electron sharing happens so that atoms get the electron configuration of noble gases. When a covalent bond forms and atoms get closer to each other, they attract. A single covalent bond is when two atoms are held together by a sharing a pair of electrons. Example H-H is equal to H:H the colon represents the shared pair of electrons since Hydrogen has only 1 electron, it forms a single covalent bond. A structural formula represents the covalent bonds by dashes - and shows the arrangement of covalently bonded atoms. Its basically the same thing as the colon, H:H or H-H. Covalent Bonds ONLY forms through Non Metals.You can draw electrons dot structures for molecules of compounds in much as the same way you draw diatomic elements. By taking the name of the element with the lowest number of electrons, and then surrounding it with the name of the element with the highest number of electrons.

Chapter 8 Summary

Section 8.1 describes what molecules and molecular compounds are. Molecules that are monatomic are consisted of only single atoms. Molecular compounds are only between non-metals. Another topic is that it tells us what a covalent bond is. It is formed by a pair of electrons by two atoms.

Section 8.2, it shows and teaches us about how covelant bonds are formed, and what type of bonds it can form. It shares that covalent bonds' electrons usually occur so that atoms attain the electron confliguration of the noble gases. An example of this would be a pair of hydrogen atoms to form a hydrogen molecule, which will attain the electron confliguration of helium, which is a noble gas and has 2 electrons. A single covelant bond joins 2 atoms which are held together by a pair of electrons. An example of how this could be written is H:H where the colon is represented by the shared electrons. Another way of writing the same formula is H-H. When there is a dash, you are writing a structural formula. It may be confusing when writing this because a similar symbol is H2. The difference is that H2 means that there are two molecules in the atom Hydrogen. H-H or H:H means that there is a covalent bond connecting two different atoms which are sharing electrons. They are drawn for molecules of compounds The opposite of this is called an unshared pair, when a pair of valece (outer) electrons that are not shared between atoms. This is also known as a lone pair or a nonbonding pair. Using dot structure can be used between 2 different atoms. Let's say we are trying to figure out dot structure for ammonia (NH3). All that would happen would have N in the middle and have the 3 H's around it. These sections have done very well explaining what it had to teach.

10.4.10

Handouts:

·         Practice Conversions – due next Monday (only if asked by Mr. Pak but should be done anyway)

·         Periodic Table

Homework:

·         Two ChemThinks – due Wednesday

    

   - Atomic Structure

   - Isotope (take notes)

In Class:

·         We were given two pages to tape into our notebooks

-Electron Configuration 1 pg.6

-Electron Configuration 1 pg.7

·         We were given practice conversion sheets which if told that you needed to do them, they are due Monday.

·         Took notes from power point on Quantum Theory (see below for notes)

·         Went to the computer lab to work on the ChemThink’s.

Power Point Notes:

        Page 1-

              Quantum Theory

o   Where are the electrons?

o   Orbitals are predictions of electron location

Page 2-

       First Quantum # -n energy levels

o   1-7

o   Describes the energy

o   The larger, then more energy and usually further from the nucleus

Picture below is of electrons placed in definite orbitals (called shells) around the nucleus.

TESTS:

·        Test - October 8^th

·         Lab Test - October 11th

Oct 29, 2010

Polyatomic Ions
In class today we learned about naming and writing formulas for ionic compounds. The chart below shows some Polyatomic Ions.

• You have to treat these as One Thing.
  Ex) write the formula for elements:

Follow steps for naming and writing formulas for ionic compounds.

1)Find the name of each element

2)Write metal first

• If the first elements are in the transition column; Sn, Pb and D-block elements; then, you use roman numerals in the name of an ionic compound.
  Ex)
  

3) Write non-metal next

• For step 3, the non-metal ends with – ide.
  Ex) carbon→carbide



• When you have a polyatomic ion you write the given names of them.
  Ex) CaCO → calcium carbonate

Upcoming event!

We have Quizzes on Monday through Wednesday! Prepare for these quizzes!.

Thursday, 10/28/2010

Bonding Habits
We learned that by looking at the periodic table you could detemine weather or not an atom is a metal or a non-metal Be is a metal. Also we learned that metals form positive ions which means that it loses electrons as in Be it loses 2 electrons making its charge +2. In addition, if an atom is a non-metal then it gains electrons as in He it gains 1 electron making its charge -1. You can determine the amount of electrons an atom will be gaining/losing by looking at the periodic table or an electron configuration. We can also find the charge of an atom by comparing the amount of electrons and protons after the atom has formed an ionic bond.

Ionic Compounds
We learned how to predict the formula of an ionic compound. First you find the charges of the ions by them already being their or you have to find that atom on the periodic table and finding its charge when it forms an ion. Then, your goal is to make the charge of the ionic bond zero. To do this you need to either double one of the ions or find the least common dinominator. Then you write it positive ion then negative ion. Ex. K+ and O2- you want to make their overall charge zero so you have -2 from K so to even that out with a + you simply just make it K2 making the formula k2O. A more challenging problem would be when you have to add a sub number to both the positive and negative ions. Ex. Fe3+ and CO32- in order to find the formula for this ionic compound you must find the least common dinominator which in this case is 6 so you would need two Fe3+ and three CO32-. The answer for this would be 2Fe(Co3)3. You need parentheses for the Co3 because that is the original ion and you don't want to get confused with how many of that ion you need to make the ionic bond come out to zero so you NEED the perentheses. In some problems you are not going to have the charges given to you so you need to look at your periodic table and find out if the ion is positive or negative and how many electrons does it gain or lose.
Then you resume the original process. Ex. K and S K's charge is +1 and S's charge is 2-. So you need to K's to even out the one S so the formula would be this K2O.

Peter I
Ionic
Scribepost
Period 2 Chemistry 2010

10.13.10

Metal Reactivity: Periodic Trends Lab

What we did today:

First We watched videos on how the Alkali Earth metals [Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium(Francium excluded because it is illegal to obtain)] react with water. These were their reactions...

Li- Floats gives off H2 gas in reaction to water

Na- Similar reaction to water as Lithium ,but reacts more vigorously

K- Gives off flame with reaction to water

Rb- Similar to potassium ,but more violent

Cs- Cesium gives off a violent explosion with reaction to water

After the videos we were asked what trend that might be noticed as we go farther down the Alkali earth family column and the answer was they were more violent in reacting with water.

Next we were ask to describe the appearences of magnesium and aluminum.

Mg- Dull strip of metal

Al- Thin metal sheet

We were then asked what happens when they are ignited.

Mg- Sparkles with a blinding white light

Al- Shrivles

Todays Lab:

In todays lab we repeated what we saw previously in the day(combining the Alkali earth metals with water). Your data table should have similar if not the same information as the the data you collected from watching the video previous in the class period.

Post Lab Questions: (Answers)

1. Is a shiny metal more or less reactive? (Shiny metals are less reactive)

2. Which metal was most reactive in the air? (Calcium)

3. Rank the metals in order of most reactive with water to least reactive. (Ca,Al,Mg)

4. Which metal reacted to produce the most OH ions? (Calcium)

5. Rank the metals in order of most reactivity with water to least reactivity with HCl. N/A

6. Rank the four metals in this lab from the most reactivity to the least reactivity. (Ca,Al,Mg)

7. What can you conclude about the reactivity of metals as you move down a column or group? (Reacts more vigorously).

8. What can you conclude about the metals as you go across the periodic table? (More reactive)

9. N/A

Don't forget to look at your schedule to see what the homework is.

That concluded the day and the next scriber will be Brandon

PLEASE COMMENT

October 6, 2010

Electron Configuration
In class today we learned more about how to find the electron configuration of a nuetral atom. The point of electron configuration is to find the location of the electron.

Shapes of Orbitals
There are four different shapes of orbitals
1) S-one orientation-holds 2 electrons
2)P-three orientations-holds 6 electrons
3)D-five orientations-holds 10 electrons
4)F-seven orientations-holds 14 electrons


The S block always starts as 1S
The P block always starts with 2P
The D block always starts with 3D
The F block always starts with 4F

EXAMPLE 1: If the electron configuration of a neutral atom is 1s2 2s2 2p6 3s2 3p6 then....
a)How many electrons does it have?
18 electrons
(there are two ways in how to find this)

1. Add all of the second numbers together (2+2+6+2+6)
2. Look at the last electron configuration, which is 3p6, and find it on your periodic table.

b)How many protons does this atom have?
18 protons
(Since this is a neutral atom, the electrons and the protons are the same amount)

c)Write the symbol for this atom
Ar
(You can find this on your periodic table)

EXAMPLE 2: Lets say you need to write the electron configuration of Bi (Bismuth). You have to start with 1s2 and end with 6p3(which is where bismuth is located) The way to find write the in between atoms is to read the periodic table from left to right.
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p2.

Orbital Diagram

Each half arrow represents how many atoms are in that row.
ALWAYS PUT ONE HALF ARROW FIRST IN EACH BOX BEFORE PUTTING THE SECOND HALF ARROW IN IT.

Ionic Electron Configuration
To write the ionic electron configuration is same as usual. Except for example if they want you to write the electron configuration of O-2, then you have to find where O is, which is 2p4, and go forward 2 because you are gaining 2 more electrons, which is 2p6 and is the atom Ne (Neon)

IN CLASS
We did pages 6, 7 and some of 11 of electron configuration.

REMINDERS
Webassigns are due on Friday. Test is on Friday.

HOMEWORK
Page 8 of electron configuration.

October 1, 2010

ATOMIC STRUCTURE: In class on Friday we defined a few terms that have to do with atoms.

Proton- It has a positive charge and its location is in the nucleus (Remember Proton is Positive)

Neutron- Neutral, it has no charge. Its location is in the nucleus as well.

Electron- Located outside the nucleus. They have a negative charge



We also learned some stuff that has to do with the PERIODIC TABLE.

-The number located above the element's symbol is the atomic number. It represents the number of protons



-The number below the symbol is the atomic mass. That stands for the number of protons PLUS the number of neutrons.



*An atom will usually have the same number of protons and electrons. When those numbers are the same, it has no charge. The only way an atom can get a positive or negative charge is by losing or gaining electrons.

EXAMPLE:

Oxygen's atomic number is 8. Therefore it has 8 protons as well as 8 neutrons. If oxygen were to GAIN 2 electrons(making its total 10 electrons), then it would have a -2 ion(charge) because it has two more electrons than protons. On the other hand, if it were to LOSE two electrons (making its total electrons be 6), then it would have a +2 ion because it has two more protons.



ATOMIC MODELS:

We learned some stuff about orbitals and relative energy and other stuff with Bohr's model, but I did not quite undestand much of that thus, I would explain it poorly. Please be sure to ask Mr. Paek about that stuff.



FIREWORKS LAB:

The purpose was to observe the recations of 7 different salts when they were exposed to fire.

PRE LAB: When electrons drop down an energy level, they give off a specific amount of energy. The energy hits our eyes, excities our neurons, and then we see color.

QUESTION: What does the term "electrons becoming excited" mean?

ANSWER: Energy is added to the electrons so they jump energy levels.



Materials: 7 salts, sticks, water, Bunsen Burner.

Procedure: 1.First we wet the stick a bit in the water

2. Then we dipped it in the salt

3. We placed it over the Bunsen Burner (while it was lit) and observed the reaction

4. Then recorded it in our table



Results:

• Li+(Lithium) Gave off a hot pink color


• Na+(Sodium) Gave off a orange color that looked like fire


• K N O3 Gave off a dull green


• K Cl Gave off a dull purple


• Sr2+ (Strontium) Was red orange


• Cu(Copper) gave off a very dull green (almost white looking)

And Cu2+ was an emerald green

At the end we has three "mystery salts" and had to figure out which ones they were based on the results of the colors we got.

Postlab:

Why did each metal salt give off a different color? That's because they had different numbers of electrons and they each went to different energy levels.

NEXT SCRIBEPOST WILL BE: Zak

9.30.10

Anouncements:

• If Mr. Paek is not in class he has asked for us to be nice to the sub
• Tomorrow we will be in the computer lab or we may do a fireworks lab
• There will be a quiz sometime next week

Homework:

• Page 118 #14
• Read pages 106-109

In class:

• Got 6 pages to tape into notebook (to be taped as shown)

- 2 Atomic Model pages

- 2 Atomic Structure pages

- 2 Rutherford Simulation lab pages

• Completed Rutherford Simulation lab with a partner

- Put black carbon paper upside down on top of a white sheet of paper with 6 circles with a small square in the middle of each one

- Take small yellow ball and bounce it on the carbon paper around 100 times

- Answer questions using calculator

• As a class we answered questions 1-8

- Do not use ruler - only a calculator - for these questions

• Talked about what the lab represented relative to Rutherford's experiment with the foil

- White paper: gold foil

- Circles: atom

- Marble: (+) random particles

- Squares: nucleus

• Finished questions 1-4 on back page of lab in class

Exam: 10/8

Lab Exam: 10/11

The next scriber will be Andrea.

9.21.10

Homework Read pgs. 106-109 and complete pg. 106 #14

Today in Class

Today in class, we worked on and finished up the Atomic Scientists worksheet. We will be able to use this on the upcoming quiz, so it is important to take good notes on scientists and their contributions to the development of the atomic theory.

We were told by Mr. Paek that are goggles needed to be in Zipblock bags incase of spread of pink eye or infection. If anyone has not done so, make sure to do it tomorrow in class.

Next, we took notes on a powerpoint that was all about the four atomic scientists. The first scientist was Dalton, who in the early 1800s contributed the solid sphere model. He concluded that each element is made of atoms, atoms of one element are identical, compounds are made from different elements in whole number ratios, and that chemical reactions involve the rearrangement of atoms. The next scientist was J.J Thomson who concluded in 1897 that negative atoms must have a negative charge, and negative is negative, with overall neutrality, then must also have a positive change. He found this out by holding a magnet to sides of a tube and noticed a bend in the light. The positive side attracted the beam and the negative side repelled the beam. Another scientist was Ernest Rutherford, who in 1911 shot an alpha particle (positive charge)through gold foil. Most all went through some had deflected. He found all atoms have a tiny positive center called the Nucleus. The last scientist was Niel Bohr who in 1914 found that electrons "orbit" around. Electrons move around the nucleus in a cloud.

Pictured below are each scientist's Atomic Model

Bottom left to right:Bohr's atom, Current orbit atom

Top left to right: Dalton's atom, Thomson's atom, Rutherford's atom

Upcoming test-October 8th, lab test-October 11th

NEXT SCRIBER ..MAHAK!

9.28.10

Homework:
Read pages 101-106 in the Chemistry Text Book. There is no question today.

Class Today:
The lab today was called the "Black Box Lab." You went around the lab stations trying to find out the blockade in the black circle container. It was filled with a bead and you had to figure out the blockade without opening the box. After you felt confident in your answer you had to write the numbger of the black box down and then draw what you thought the blockade was. It was extremely confusing and difficult, often leading to extremely odd answeres from some of the class members.

This however was an extremely amazing metaphor for scientists Dalton, Rutherford, Bohr and Thomson whom all tried to decide what the shape of an atom was. They didn't have any microscopes that could see anything that tiny. Hence, the "Black Box Lab."

Reminder:
There is going to be a quiz on all four of these scientists soon. Do the worksheet assigned today that you can use on the quiz. Take notes from the four sheets that Mr. Paek gave us and you'll be good to go.

Also, the test is on Oct. 8th and the Lab test is on Oct. 11th.

Plus, if you want to retake your Lab Test, then tell Mr. Paek what day and period you're coming in.

The next scriber will be Kaylee.

9.27.2010

UPCOMING:
We will be having a Conversions Quiz either sometime this week or next week.

HOMEWORK:
no homework was assigned today.

BEGINNING OF CLASS:
Our lab notebooks were handed back but Mr. Paek did not get a chance to grade them. There were 4 sheets at the front that needed to be picked up.

Those sheets included 2 pages of the Unit 2 Schedule and the other 2 included the newest lab we will be doing this week called The Black Box Lab. (Also make sure to leave an open page between the Unit 2 Schedule and the New Lab.)

DISCUSSION:
Mr. Paek then mentions our Unit 1 Lab Tests and how the average of all the periods was VERY low. But on the bright side our Unit 1 Tests had very high marks. For our Lab Tests, if you decide to, you may retake them individually WITH the full 50 minutes.

The Lab Test has been improved where Mr. Paek added specific questions to guide you if you're completely lost on how to do this lab. You may retake them during lunch or after school by visiting Mr. Paek, NOT the TLC or testcenter.
Overall, the Unit 1 Tests turned out to be very good for most classes. Near the end of class Mr. Paek answered questions that we may have had relating to the Unit Tests.

END OF CLASS:
Our grade reports were handed back at the end of class today. Mr. Paek decided that he would not include the grades titled 'Texting', and also 'OnMyMind'.


the next scribe will be...RAINA!!

9/21/2010 Blog

Upcoming Events:
-Wed: Lab Test
-Thurs: Test, study using class blog and in-class notes
-Fri: Chem Day (same thing as Bio day, apparently better)
Homework:
-Study for Lab Test, Tomorrow
-Study for Chapter Test, Thursday
-Post 2 comments on Blogger- Go to Period 2 Chem Blogs, go through the list of blogs. Select 2 of the blogs on list and comment on something about the post. Don't be too brief, suggest what can be done to make it better, or what they did a good job on.
- Complete the 4 Chem Review pages
- Complete Chapter 1-2 Review sheet
- Mr. Paek collecting journals, Thursday. Make sure no falling papers
Overview of Today:
Today in class we talked about the information listed above. Then with the remainder of class we completed the 4 pages of "Chemistry Basics Review." Some people able to complete in class, if not completed in class, then rest that was not completed is for homework. Here are the pictures of the in-class work/homework if not completed. These pages have my answers to the "Chemistry Basics Review" pages and there is no guarantee for correct answers.

Next Blogger: Rachel Mitchell (voted by class)

9.20.2010

REMINDER:

1. Go study off the blog
2. Mr. Paek is collecting the study guides Thursday
3. The lab test is Wednesday and the real test is on Thursday
4. web assigns are due tomorrow
5. need two comments on someones scribe post

Today in class we took a quiz, if you did not take it then go to the test center it should be in there.

The next scriber will be.... John.

The Scribe List

This is The Scribe List. Every possible scribe in our class is listed here. This list will be updated every day. If you see someone's name crossed off on this list then you CANNOT choose them as the scribe for the next class.

This post can be quickly accessed from the [Links] list over there on the right hand sidebar. Check here before you choose a scribe for tomorrow's class when it is your turn to do so.

IMPORTANT: Make sure you label all your Scribeposts properly (Your display name, unit title, scribepost, and p2chem2010) or they will not be counted.

Jimmy          John A.   Andrea          Max       Micaela    Kimmy          Frankie          John H.            Ose            Agatha          Zak          BigMoneyBen          Mahak          Kevin          Paul          Rachel             Elizabeth     Raina           Monica          Kaylee          Yassine          Jill          Vit          Michael          Brandon

Friday 9.17.10 - Matter Lab

REMINDER: Extra credit packet available in the TLC. Look in the bin for the lab we worked on Friday.



HOMEWORK: Webassign due Monday along with review sheet.



LAB:

We worked on a matter lab. We went from station to station looking at models of different atoms and molecules etc. We had to draw what we saw then write the formula of it. Finally we described it (compound, pure substance, element etc.)

EX: Picture: Formula: Terms:
oo oo ooo, 2N2 +N3, Element, pure substance, molecule

NEW TERM:
diatomic molecules- molecules that will always be in pairs when they are alone

H O N Cl Br I F (sound out the word to remember the elements)

Ex: oxygen (O) will always be O2

Scribepost Format

Title:  day and date - for example - 11.13.10

Announcements - put any here

Homework -  put any here

Body:  this is solely up to you how you do this.  please remember, you don't do many of these - do yours the best that you can - for yourself and for your classmates.  Headings in bold, pictures, videos, examples, announcements, homework are some of the elements that make for a successful post.

End with a pick of who the next scriber will be.

Labels: Need 4 of them:

1. your display name
2. unit name
3. scribepost
4. p2chem2010

Thursday 9,16,2010

Today in the beginning of class Mr Paek made a couple of announcements about the upcoming week, here are the dates:

• chem think is due tomorrow-17/9
• web assign is due Monday-20/9
• Quiz on Monday-20/9

Quiz will be on molecules,atoms,compounds, the quiz will also have like 1 density problem and 1 measuring problem.

• lab test Tuesday-21/9
• test - sometime during the week.

Then Mr Paek explained to us the difference between physical and chemical change:

-physical change: do not affect chemical position.

some chemicals present.

same arrangement of atoms.

-chemical change: alter chemical composition

new chemicals formed

bonds broken and formed

rearrangement of atoms

after we did a chemical and physical changes sheet. we had 17 examples, where we had to decide weather the change is physical or chemical.

-some examples:

snow turning into water= physical change

hammering gold into a thin sheet=physical change

phosphorus burning=chemical change

We then did the physical or chemical stations lab: the lab was really easy we had to go through stations.

examples= in station 1 we had to watch melting candle wax, which was physical change. then burn candle wax and wick, which was a chemical change.

in station 4 we had to add water and food coloring, which was physical change. then melt ice in water which also was physical change.

Semptember 15 2010

Today we got 2 sheets for an online activity we did for most of the day. the 2 sheets can be found in the front right of the room in the box. The sheets were about a website chemthink where we practiced stuff having to do with elements atoms and molecules.

go to http://www.chemthink.com/ and use this code to sighup 4160-3702-9971 next set up your account. make your username your first initial and your last name.

After you sighn up click on introduction Particulate nature of matter then tutorial. After your done with the tutorial click on question set and try to get 10 right before 3 wrong for credit.

Tuesday 9.14.2010

Today in class we learned about atomic level pictures. We defined the terms:

• atom - most basic unit of matter
• molecule - group of atoms help together by a chemical bond
• element - made up of single type of atom
• compound - molecule made up of more than one kind of atom

Then we did a couple of problems from the worksheet to furthermore explain the difference of these four terms and learn to distinguish them.



In this problem we had to decide for the each of the atomic level diagrams whether they are elemets or compounds and consisting of either atoms or molecules.

Then we defined two more terms:

• pure substance - all the same
• mixture - has different kinds

To get a better understanding of what these terms we did another problem from the worksheet.



We also learned how to write formulas for atomic level pictures.



After that we practiced drawing the atomic level pictures according to the formulas that were given.

Then we had even more practice with writing the formulas and descriptions for the atomic level pictures and also drawing the atomic level pictures based on the formulas.





Once we were done with everything, we had some time to just talk to other people untill it was time to go to the fall sports assembly.