1. 1. What are the three rules that govern the filling of atomic orbitals by electrons?
Aufbau principle- electrons enter the lowest energy first.
Pauli Exclusion Principle- at most 2 electrons per orbital (different spins)
Hund’s Rule- When electrons occupy orbitals of equal energy they don’t pair up until they have to.

2. 2. Draw the orbital diagrams for the elements that are identified only by these atomic numbers.
a) 15 b) 12 c) 9 d) 18
a) 15 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑ ↑
1s2 2s2 2p6 3s2 3p3
b) 12 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓
1s2 2s2 2p6 3s2
c) 9 ↑↓ ↑↓ ↑↓ ↑↓ ↑
1s2 2s2 2p5
d) 18 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓
1s2 2s2 2p6 3s2 3p6

3. 3. What is meant by 3p3?
Three electrons in the p sublevel
of the 3rd principle energy level.
# of electrons
principle energy level 3p3
sublevel

4. 4. Write complete electron configurations for each of the following atoms.
carbon c) fluorine
argon d) rubidium
a) C 1s2 2s22p2
b) Ar 1s2 2s22p63s23p6
F 1s2 2s22p5
Rb 1s22s22p63s23p64s23d104p65s1

5. a) 4s b) 3f incorrect c) 2d incorrect d) 3d
5. Indicate which of these orbital designations is incorrect.
a) 4s b) 3f c) 2d d) 3d
a) 4s
b) 3f incorrect
c) 2d incorrect
d) 3d

6. 6. What is the maximum number of electrons that can go into each of the following sublevels?
a) 2s
b) 3p
c) 4s
d) 3d
e) 4p
f) 5s
g) 4f
h) 5p
a) 2 e-
b) 6 e-
c) 2 e-
d) 10 e-
e) 6 e-
f) 2 e-
g) 14 e-
h) 6 e-

7. a) Se 4s24p4 b) V 4s23d3 c) Ni 4s23d8 d) Ca 4s2
7. Write the valence electron configurations for these elements.
selenium b) vanadium
c) nickel d) calcium
a) Se 4s24p4
b) V 4s23d3
c) Ni 4s23d8
d) Ca 4s2

8. a) [Ne] 3s23p6
b) [Kr] 5s24d5
c) [Xe] 6s2

9. a) 3s1 Na - Sodium b) 2s22p3 N - Nitrogen c) 3s23p2 Si - Silicon
a) 3s1 Na - Sodium
b) 2s22p3 N - Nitrogen
c) 3s23p2 Si - Silicon
d) 2s22p4 O - Oxygen
e) 4s2 Ca - Calcium
f) 4s23d2 Ti - Titanium

10. 10. How many paired electrons are there in an atom of each of these elements?
helium 2 (no unpaired)
b) boron 4 (1 unpaired p)
c) sodium 10 (1 unpaired s)
d) Oxygen 6 (2 unpaired p)

11. 11) List the colors of the visible spectrum in
order of increasing wavelength.
Violet Indigo Blue Green Yellow Orange Red
Shorter wavelength → Longer wavelength

12. 12) Arrange the following EM radiations in
order of decreasing wavelength.
d. Radio Longer
Infrared
Green ↓
Ultraviolet
c. X-ray Shorter

13. 13) Use a diagram to illustrate the following:
Wave cycle
Amplitude
Wavelength

14. 14) What is the wavelength of radiation whose
frequency is 1.50 x 1013 s-1?
λ = c v
= x 108 m/s
1.50 x 1013 s-1
λ = x 10-5 m

15. 15. Suppose that your favorite AM radio station broadcasts at a frequency of 1150 kHz.
What is the wavelength (in centimeters) of the radiation from the station
λ = c v
= x 108 m/s
1.150 x 106 s-1
λ = x 102 m = 2.61 x 104 cm

16. 16) What is the energy of a photon of green
light whose frequency is 5.80 x 1014 s-1?
E = h v
= (6.62 x J s) (5.80 x 1014 s-1)
= 3.84 x J

17. 17) A mercury lamp emits radiation with a
wavelength of x 10-7 m.
What is the wavelength in centimeters?
4.36 x 10-7 m = 4.36 x 10-5 cm
b. Calculate the frequency of this radiation.
v = c λ
= x 108 m/s
4.36 x 10-7 m
v = x 1014 s-1

18. Calculate the energy of a photon of red
light whose wavelength is 6.45 x 10-5 cm.
6.45 x 10-5 cm = 6.45 x 10-7 m
v = c λ
= x 108 m/s
6.45 x 10-7 m
v = x 1014 s-1
E = hv = (6.63 x J s) (4.65 x 1014 s-1)
E = 3.08 x J