Periodicity

Friday, December 14, 2012

Due Monday: Alternate Universe Chemistry Worksheet and the Metal Reactivity Lab. The test is on Tuesday.

Today in class we learned everything there is to know about Periodicity. Mr. Lieberman showed us a couple of videos about how the Alkali Metals react with water. Then he showed us his own demonstration of how Aluminum and Magnesium react with air through a flame.  Aluminum had nearly no reaction and Magnesium had a vigorous reaction.  After this, we conducted our own lab to discover some periodic trends involving the reactivity of metals.

Reaction with Aluminum








Reaction with Magnesium

These were the results from my lab.  We tested reactivity of the metals: Calcium, Aluminum, and Magnesium with water and with Hydrochloric Acid.  We saw that Calcium was the most reactive in both cases.  We saw that Magnesium had a slight reaction with the two solutions.  We could not detect a reaction with the Aluminum in either of the solutions.  With this information, we could deduct certain information pertaining to periodic trends. We could clearly see that as you move across the periodic table, from left to right, reactivity decreases. (Magnesium more reactive than Aluminum.  We could also see that as you move down a column of the Periodic Table,  reactivity increases. (Calcium greater reaction than Magnesium)




Reactivity decreases for metals as you move across a row because it becomes harder for them them to lose electrons.  It increases as you move down a row because it becomes easier to lose an electron. We saw this in the videos we watched with the Alkali Metals. The reactions kept getting bigger and bigger all the way until Cesium's reaction with water made the bathtub explode.

The next scribe will be... JANE B

December 13

Thursday, December 13, 2012

Due Tomorrow: Periodicity Worksheet. The Alternate Universe Chemistry worksheet is not due until Monday. THE TEST HAS BEEN MOVED TO TUESDAY, 12/18.

Today in class, we spent the majority of the class going over the class notes. We learned about atomic radius, ionization energy, and a little bit of electronegativity.

     Atomic radius, simply put, is the radius, or size, of an atom. We learned that similarly to the Periodic Table of the Aliens, as you move up and down columns and left to right through the rows of the periodic table, the elements have similarities as well as one or two changing variables. For atomic radius, as you move left to right on the periodic table, the radius decreases. This is because as you move left to right, the elements have more protons, which bond with the electrons, drawing the atom tighter together, making the radius smaller. We also noticed the trend that, as you move down the families, the radii increases because there are more electrons as you move down, but not as many protons, which means that the size (radius) will increase. This trend is the opposite for both ionization energy and electronegativity.

     Ionization energy is the amount of energy required to remove one valance electron (an electron on the outer shell of the atom) from the atom. As I mentioned above, the trends of ionization energy are opposite to the trends of the atomic radius. As you move from left to right on a period, the energy needed to remove one electron increases. This is because as you move across the period, as mentioned above, the elements gain protons, drawing the atoms tighter together. Because the elements become more compact, the energy needed to pull one electron out increases. Similarly, as mentioned above, as you move down a family, the amount of electrons increase, but the amount of protons does not, so the atoms are less compact. This makes the amount of energy needed to pull out one electron less.

     The trends of electronegativity are exactly the same as ionization energy, for similar reasons. Electronegativity is the ability of an atom to attract electrons. As you move left to right across a period, the outer shell of atoms becomes more full. This means that as you move left to right, atoms need less and less electrons. The pull that they have to complete their electron shells becomes greater.

Go on Moodle if you need tonight's homework.

The next scribe will be.... Jack M.

SPDF orbitals

Due on Thursday: Periodicity Questions (word processed) and Periodic Table of Aliens. The Alternate Universe Chemistry worksheet is not due until Friday. Also, the test date has been CHANGED to Tuesday, December 18th. Alrighty now that that's settled, lets get on to the fun stuff!

In class on Monday, Mr. Lieberman explained that when different elements are burned, their flames change to different colors because they are giving off light as they burn. For example, when different S¹elements are mixed with Nitrate and dissolved in methanol, their flame changes from the blue color of a methanol flame to whichever color of light it gives off. From left to right, the elements in the dishes are Lithium (pink/red), Sodium (orange/yellow), Potassium (light violet), and Copper (green).

After that, we played battleship to learn the order of SPDF orbitals and how they appear in the periodic table.  Basically, the first two columns of elements end in S orbitals, the bottom two rows of the periodic table end their electron configuration in F orbitals, the transition metals end in D orbitals, and the last 6 columns end in P orbitals. Therefore if we read it from left to right, the order would be SFDP.

Now on to Tuesday's class, WOOHOO!

OK so on Tuesday we received a new set of notes which are available on Moodle. We also talked more about the properties of SPDF orbitals.  Mr. Lieberman gave us a ton of sheets for practice with the orbitals and their order, check above for the specific due dates.

Other than that, nothing especially new happened. If you are confused or have questions about the unit, feel free to email Mr. Lieberman at dlieberman@glenbrook225.org.

The next scribe will be..............................................BRIAN F.

Electron Configurations

On Friday in class, we found out that Mr. Lieberman is moving to Florida to run his own hotel.
Also, we found out that he needs to fill up every room on each floor before he can begin to fill the rooms on the next floor, much like how you need to fill the S orbitals before the P orbitals, and so on.

S orbitals can fit 2 electrons, much like the Suites per floor in Liebs' hotel can fit 2 people.
P orbitals can fit 6 electrons, much like the Pretty rooms per floor in Liebs' hotel can fit 6 people.
D orbitals can fit 10 electrons, much like the Dungeon rooms per floor in Liebs' hotel can fit 10 people.
F orbitals can fit 14 electrons, much like the F (unknown meaning) rooms per floor in Liebs' hotel can fit 14 people.

Electrons can be configured using the periodic table.
Hydrogen and Helium compose the 1s energy level, then the 2s-7s orbitals are composed of the elements in columns 1 and 2 of the Periodic Table so...

2s = Li and Be

3s = Na and Mg

4s = K and Ca

And so on...

P orbitals start at an energy level of 2, so instead of P orbitals starting with 1p, the P orbitals start with 2p.
P orbitals include columns 13-18 of the periodic table (not including Helium) so...
2p = B, C, N, O, F, and Ne
3p = Al, Si, P, S, Cl, and Ar
4p = Ga, Ge, As, Se, Br, and Kr
And so on...

D orbitals start at an energy level of  3, so instead of D orbitals starting with 1d (not One Direction), the D orbitals start with 3d.
The D orbitals include rows 3-12 so...
3d = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn
4d = Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, and Cd
5d = La, Hf, Ta, W, Re, Os, Ir, Pt, Au, and Hg
6d = Ac, Rf, Db, Sg, Bh, Hs, Mt, Ds, Uuu, and Uub

F orbitals consist of the Lanthanide Series and the Actinide Series, or the two rows that were moved aside to allow the Periodic Table to fit on a piece of paper. F orbitals start at an energy level of 4, so instead of F orbitals starting with 1f, the F orbitals start with 4f. So...
4f = Ce, Pr. Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Tb, and Lu
5f = Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, and Lr

Those are the energy levels, now we need to configure the electrons. When writing out the electron configuration of an element, you need to go row by row and go in order as orbitals are added on.
An example helps explain this concept.

When writing the Electron Configuration for Bismuth, or Bi, you need to go in order of the orbitals. So...

1s^2 because the entire S orbital is filled with 2 electrons.
2s^2 2p^6 because the entire S and P of row two are full of electrons.
3s^2 3p^6 beause the entire S and P orbitals are full of electrons.
4s^2 3d^10 4p^6 because the entire S, D, and P orbitals are full of electrons. D comes before P because the D block (group of columns) comes before the P block when reading left to right.
5s^2 4d^10 5p^6
6s^2 4f^14 5d^10 6p^3 because the entire S, D, and F orbitals are full of electrons. The f comes before the d because the f block comes before the d block in the 6th row of the Periodic Table. 6p^3 because Bismuth is the 3rd element in that energy level of the p block with Thallium (Th) and Lead (Pb) coming before it.

The final Electron Configuration for Bismuth (Bi) is:
1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2 4f^14 5d^10 6p^3

The number of electrons for the element can be determined by counting the exponents of the Electron Configuration if the element is an ion, or by looking at the Atomic Number of the element if it it neutral.

Hope this helps!
Homework: Electron Configurations packet, the first four pages.

The next SCRIBE will be GEORGIA K.

Spectrum and quantum numbers

We started class by discussing about the electromagnetic spectrum. Mr. Lieberman then passed out these glasses to everyone in the room.

He told us to look at the lights in the room with the glasses on. You would see something similar to this.

These are called continues spectrum. The glasses makes the light bend into different colors. Then, he took out a tube filled with hydrogen gas. He put it in a machine that gives off energy. He then turn off all the lights, and this is what we see.

sorry its blurry!

Then, we put on our glasses, and this is what we see.

These are called line spectrum. Different frequency effects different wavelengths. Again, this happen because the glasses bends the light, making them break through its components.

We then go over the notes. We went over the Spectrum all the way to the quantum numbers. When there is energy, electrons jump up and then back down. When the electrons jump down, they release energy/light. We then went over quantum numbers. Here's a video explaining the quantum numbers.

Feel free to email Mr. Lieberman or go to the TLC if you still do not understand this.

HOMEWORK: Quantum Number worksheet and go on Moodle for a new schedule for this unit.


Next Scribe: Katie W.

Molar Volume of a Gas

HW due today: Gas problem set #1 & 2.
HW: Molar Volume of a Gas Lab is due Wednesday! Also, there is a WA reading 5.4.
 *If you have questions from the two worksheets, we will go over it in class tomorrow.


Hello, this is Eunice! Today in class we did the Molar Volume of a Gas Lab the entire class period. Our lab goal is to measure the molar volume of hydrogen gas at STP. If you don't know what molar volume is, it is the volume occupied by one mole of a gas is called the molar volume. During this experiment, we measured the molar volume of hydrogen gas as standard temperature and pressure. The reaction is Mg(s) + 2HCl(aq) --> MgCl_2(aq) + H<sub>2(g).


First, we got a piece of magnesium and tied it around a copper wire like a ball.  
Then, my partner got 10 mL of hydrochloric acid and poured it at the bottom of a eudiometer. Next, we filled a beaker with 600mL of tap water.  
Later, we used a smaller beaker to put in water into the eudiometer to the top. We put in the copper wire with magnesium inside, plugged it with a rubber stopper, and flipped the eudiometer over into the tap water. There was a lot of bubbling and sizzling inside, so we waited until there were no bubbles left. Then we measured the volume inside, and we got 26.3 mL. Share your trial data with your table and make sure you have both trial 1 and trial 2. 
After you record the length of Mg ribbon, mass of Mg, evidence of chemical reaction, volume of H2 gas, barometric pressure, room temperature, and water vapor pressure, go on to the calculations part! 

BTW, remember:
Total Pressure= pressure of H2O + pressure of H2.
10cm of Mg=.1407grams
Barometric pressure=30.04 in Hg.</sub> 

                                     Get 600mL of water and be ready to flip over the eudiometer!

                                                 This is not a great picture. But you should tie the magnesium
                                                with copper wire like a ball. And put in rubber stopper.

                                           Flip over the eudiometer quickly and carefully.
                                            You will see lots of bubbles!! (H2)

                                                  This is an awesome picture of the bubbles!
                                                         The magnesium disappeared.
                        
                     

                       

Next Scribe is: BENYA C

 

  

Gas Stoichiometry

Due Today: Ideal Gas Law worksheet
Due Tomorrow: Ideal vs. Combined worksheet
                                       Gas Stoich #1 worksheet

Today we learned how to do gas stoichiometry. Basically, we use stoichiometry to solve the equations of the different gas laws.

Today's demo was all about pressure of gas in a cannon.

                                                                                                                      

 After the demo, we had to answer a couple questions about it that would lead to gas stoichiometry:

 CaC₂ + 2H₂O --> C₂H_2(g) + Ca(OH) ₂

1.) How many moles of gas are formed in the cannon?

     To solve this problem, we use gram-->mol stoich:

 

     0.41g x 1mol CaC₂ x 1mol C₂H_{2  = 0.0064mol}

                        64 g         1 mol CaC₂

 

2.) What is the pressure of the gas that was formed in the cannon?

      To solve this problem, we first found all the variables of the ideal gas equation: PV=nRT. We used this equation because there is only one set of conditions.

 

       T = room temperature = 23°C = 296K

       n = 0.0064

       V = pr² h = p(2.68)² (41) = 870 cm³ = 870mL = 0.87L

       R = 0.00821 (atm/mol K)

The equation to solve for P is:

       (P)(0.87) = (0.0064)(0.00821)(296)

                    P = 0.18atm

 

This example should help with the Gas Stoich homework sheet. The other sheet for homework is review for the quiz tomorrow :)

 

 

 

 

 

 

 

 

 

 

Next Scribe: Eunice C.