Chapter 3
1. A Helium-Neon (HeNe) laser emits light at 633 nm. What color light is this?
633 nm is red
2. Complete the following table for neutral atoms
Name
of
Elements
Nitrogen
Calcium
Strontium
Silicon
Barium
Symbol
N
Ca
Sr
Si
Ba
Atomic
Number
7
20
38
14
56
Mass
Number
14
40
88
28
137
Number
of
Protons
7
20
38
14
56
Number
of
Neutrons
Number
of
Electrons
7
20
50
14
81
7
20
38
14
56
3. What are the elements that contain each of the following numbers of protons? Give
their names and chemical symbols.
a.
b.
c.
d.
e.
1, Hydrogen (H)
76, Osmium (Os)
29, Copper, (Cu)
21, Scandium (Sc)
95, Americium (Am)
4. Sort the following forms of electromagnetic radiation in order of increasing energy.
d. Blue light
a. Infrared light
c. FM radio waves
b. AM radio waves
5. What happens when an electron collapses back to its ground state from an excited
state?
The electron emits/releases the same amount of energy it originally absorbed.
6. Draw a diagram for the electronic configuration of the following elements.
See Ch. 3, Table 3.3
a. Sodium
c. Aluminum
e. Phosphorus
b. Magnesium
d. Silicon
f. Argon
7. How many valence electrons does each element have in Question 6?
a.
b.
c.
d.
e.
f.
Sodium, 1
Magnesium, 2
Aluminum, 3
Silicon, 4
Phosphorus, 5
Argon, 8
8. Classify each of the following as a solid, liquid, or gas at room temperature.
a.
b.
c.
d.
Mercury, Liquid
Helium, Gas
Oxygen, Gas
Gold, Solid
9. Classify each of the following elements as a metal, a nonmetal, or a semimetal.
a.
b.
c.
d.
e.
Helium, non-metal
Sodium, metal
Iodine, non-metal
Calcium, metal
Boron, metalloid