10.13.10

Wednesday: late arrival! :) 35 min period

At the beginning of the period, Mr. Paek showed us a few vidoes on metal reactivity. He explained how the periodic table consists of different families:
Row 1(downward) - Alkali metals
Row 2(downward)- Alkaline earth metals
D Block(sideways)- Transition metals

The vidoes consisted of experiments about the reactions of the alkali metals and water. The farther down the row in the periodic table, the stronger/more intense the reaction. In one of the videos, it included an experiment with a glass. The metals were put in the water one by one:
Li- Floated on the water while giving off hydrogen
Na- The same as Li, but a more vigorous reaction. Na gave off much more hydrogen
K- Produced sparks and a small fire
Rb- Produced bigger sparks and bigger fire
Cs- Completely shattered the glass cup

After watching the vidoes, Mr. Paek introduced a short lab. The metals that were being tested were calcium, magnesium, and aluminum. We placed these metals into well plates and used water, HCL, phenolphthalein indicator (PHTH) (liqiud) to see how they would react with the metals. Her is the data:
Appearance:
Ca- little rocks
Mg- thin metal sheets
Al- Flat rocks

PHTH:
Ca- water turns pink
Mg- magnesium sheet turns pink
Al- water becomes cloudy

Water:
Ca- sizzles and dissolves
Mg- nothing
Al- nothing

HCL:
Ca- sizzles and disolves a little
Mg- sizzles and gives of hydrogen
Al- nothing

PHTH and HCL
Ca- turns pink
Mg- nothing
Al- nothing

NO HOMEWORK!!!
Next Scriber: Sal :)

Friday October-1-2010

To start class Mr. Paek went over the previous days scribe post. Then he started giving us notes in the papers labeled Atomic Models. Then we started the fireworks lab.

PreLab: when electrons drop DOWN an energy level, they give off a specific amount of energy in the form of electromagnetic radiation. This energy then strikes our eye, causing chemical reactions in the eye that excite neurons and thus we perceive color. The electrons for metals in particular have energy levels far enough apart to cause colors in the visible spectrum

What does the statement, “Electrons can become excited,” mean?

The purpose was to observe the different quantum leaps of electrons in several metal salts. Basically at each lab station, there were cups of different salts, metal splints and a Bunsen burner. When we got the splint wet, we covered the end with salt, and stuck it into the flame. Depending on the salt, the flames changed colors like bright red, blue/green and others.

On the lab sheet, you had to describe the specific color given off by each metal salt and the go to the front of the room where Mr. Paek had 3 different unknown salts that he showed us on the bunsen burner and depending on the color and our resulfs from the other lab stations, had to deduct what they were. the bell rang before we finished the post lab questions so Mr. Paek just said we'd go over those on Monday. Happy Homecoming!