Trends in the Periodic Table

12/13/13
We had a sub today for our quiz. We were given the whole period for the quiz, but if you finished early you were to start working on the Coulombic Attraction Packet, which was due Monday


12/16/13

To start class:
Mrs. Friedman reminded us that because we are being given less help this chapter, there will not be a video posted before the test. The test is on Thursday and the review will be Wednesday in the morning instead of Thursday.

After that, we went over our homework. Note: for #7 of page 4, you couldn't find the mass number because you weren't given the number of neutrons. A key thing to remember about the Coulombic Attraction Packet is that as the distance between the electron(s) and the proton(s) increases, the force of attraction decreases. In order to increase the force of attraction while the distance stays the same, the number of protons must increase.

Trends in the Periodic Table

1) Atomic Radius (aka atomic size)
2) Ionization energy
3) Electronegativity

Today we only got through the trend of atomic size. The notes are posted on moodle, but here is the basis of it:
a) As you move down the columns of the periodic table, the size of atoms increase.
Ex. A hydrogen atom is smaller than a lithium atom, which is smaller than a sodium atom.


b) As you move from left to right on the periodic table, the size of atoms decrease. This is because the added protons will increase the force of attraction and make the atom more compact. The added electrons remain on the same energy level as the previous farthest electrons and will space out from the other electrons, thereby adding little force to compete with the nucleus.
Ex. A sodium atom is smaller than a silicon atom, which is smaller than a argon atom.



Homework:
The review packet is due tomorrow.
Finish the 4 sheets that were handed out today (on moodle)
Check your Coulombic Attraction packet with the key on moodle.

The next scribe is..
Suvd D

Colligative Properties

Video:
We started off the class with a video on soda slushies. Later in the class we learned why this works.

Colligative property notes:
These kind of properties are physical properties of solutions that depend on how many solute particles are present, NOT on what the solute is.

Aqueous solution equations:
molecular- C6H12O6(s) ---> C6H12O6(aq) 1 mole particles
ionic- NaCl(s)---->Na+(aq) + Cl-(aq)  2 moles particles

This is why ionic compounds are more effective for colligative properties.

Two colligative properties:
The two main properties will focus on are Boiling Point Elevation and Freezing Point Depression.

Boiling Point:
The ions of a solute block the water from escaping. The water requires more energy to escape the container and so the boiling point is raised.

Freezing Point:
When a solid is formed, it can be thought of a crystal forming. More solute in a solution makes the formation of these crystals require more energy. Thus, the freezing point is lowered.

Solubility of Solids v. Gases:
As we as learned, a solid's solubility is increased when the temperature is increased. With gases however, the solubility decreases with an increase in temperature. Another way to affect the solubility of gases is with pressure. By increasing the pressure of a gas, the solubility increases.

Also, I'm sorry that this is late.

The next scribe is:
Daniel W.