Review Question 29

29)
      a. Looking at the trends in first ioniaztion energies across period 3, there is a sudden unusual dip with Al and S. First ionization energy is the energy required to remove the first electron from an atom. This means that it is much easier to remove an electron from S than it is to remove one from Al, because the extra electron in the p shell of S repels the other electron, making it much easier to remove.
     b. Electronegativity is the ability of an atom to attract another electron. Electronegativity increases across the groups and decreases down the periods, which makes the halogens the most electronegative group. The noble gases have an electronegativity of zero, because all of their electron shells are filled, and they don't want to attract another electron.
    c. Atomic radius is the average distance to the nucleus of the atom from the edge of its surrounding electron cloud. Oxygen would have the smallest atomic radius becuse atomic adius increases down the periods, but decreases across the groups.

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18. What is the explanation for the discrete lines in atomic emission spectra? How did this affect the model of the atom?

An atomic emission spectrum is obtained by splitting the light emitted from an atom with a prism. This forms discrete lines with their own color (frequency), which each correspond to a certain quantum of energy.

This means that electrons could only be found in very specific energy levels rather than just floating around wherever they wanted.

Bohr formed his progressive (and incorrect) model of the atom by observing the atomic emission spectrum of hydrogen.

Household Substance Experiment: Vanilla

For this experiment, we were required to choose a household substance, and name five physical and five chemical of the substance. I chose vanilla extract (hence the title). The vanilla extract was a rich brown in color, had a sweet odor, and a volume of 5 mL. Vanilla is also liquid at room temperature, and has a boiling point of 78.3°C to 100°C. Some chemical properties of vanilla are flammability, non-reaction with bases and solids, and acidity. Color, odor, phase, and boiling point are intensive properties. Volume is an extensive property. To determine the chemical propeties of vanilla, I conducted a series of experiments. The first experiment was to determine whether or not vanilla is flammable.
First, I measured out 5 mL of vanilla and put it into a non-flammable container.

Then, I lit a match, and set the vanilla on fire.

I concluded that vanilla is indeed flammable, due to its high alcohol content.

For the second experiment, I tried to determine the reaction of vanilla to acid.
First, I measured out 2.5 mL of vanilla.

Then, I measured out 15 mL of vinegar.

I mixed the two together and observed the reaction.

.....

It wasn't very exciting.
I concluded that vanilla has a low reactivity to acids.

For the final experiment, I determined vanilla's reaction to a base.
First, I measured out 2.5 mL of vanilla.

Then, I measured out 2.5 mL of baking soda.

I mixed them to tether, and observed the reaction.

I concluded that vanilla has a low reactivity to bases.

This wasn't very exciting either.