Chemistry 1
HH#3.5
1. For two electrons to occupy the same
orbital they must
(A)
have opposite spins.
(B)
be oppositely charged.
(C)
enter the orbital simultaneously.
(D)
have the same spin value.
(E)
remain at constant distance from the
center of the mass.
2. The correct electronic configuration for the
23
sodium atom, 11 Na, is
1s22s22p6
(B)
1s22s22p63s1
(C)
1s22s22p43s23p1
(D)
1s22s22p82d103s1
(E)
1s22s22p62d103s23p1
3. Which is the electronic configuration for
the scandium atom, 21Sc ?
(A)
[Ar]
(D)
[Ne]3s23p3
(B)
[Ar]4s2
(E)
[Kr]
(C)
[Ar]4s23d1
4. How many unpaired electrons are in a
ground state 44Ru atom?
0
(B)
1
(C)
2
(D)
3
(E)
4
5. Which atom contains a partially filled 3p orbital?
(A)
iron
(D)
calcium
(B)
argon
(E)
aluminum
(C)
boron
6. Which electronic configuration represents
the sodium ion, Na+, in its ground state?
(A)
1s22s22p6
(D)
1s22s22p63s2
(B)
1s22s22p53s1
(E)
1s22s22p63s23p2
(C)
1s22s22p63s1
7. Which electron configuration represents an
atom in an excited state?
(A)
(A)
Quantum/EConfig
(A)
1s22s22p6
(B)
1s22s22p63s2
(C)
1s22s22p63s23p64s23d1
(D)
1s22s22p63s23p64s24p1
8. What are the four quantum numbers for
the “last” electron placed in 22Ti?
(A)
4, 0, 0, +1/2
(B)
3, 3, –2, +1/2
(C)
3, 2, –2, –1/2
(D)
3, 2, –1, +1/2
9. A magnesium ion, Mg2+, has the same
number of electrons as an atom of
(A)
(D)
neon. (B)
fluorine.
sodium
(C) calcium.
10. When an electron shifts from one energy
level to a higher level in the same atom, energy is
absorbed. Which of the electron transitions
represented below absorbs (that is, requires) the most
energy?
13. Which diagram represents the shape of
all of the orbitals in the 2p sublevel?
(A)
(B)
(A)
(C)
A
C
(B)
(D)
11. Which electron configuration represents a
transition element?
(A)
1s22s22p63s2
(B)
1s22s22p63s23p6
(C)
1s22s22p63s23p64s1
(D)
1s22s22p63s23p63d3 4s2
z
B
D
(C)
y
x
z
(D)
y
12. Which particle has the same electron
configuration as an atom of argon?
(A)
(D)
Ca2+ (B)
Cl+
Na+
(C)
K
x
–
14. A single burst of light is released from an
atom. Which statement explains what happens in the
atom?
(A)
An electron is changed from a particle to
a wave.
(B)
An electron moved from a higher to a
lower energy level.
(C)
An electron pulled a proton out of the
nucleus.
(D)
An electron pulled a neutron out of the
nucleus.
Chemistry 1
HH#3.5
Quantum/EConfig
15. Give the noble gas abbreviated electron configurations for Br and Co.
16. Draw the orbital diagram for the highest energy sublevel in 45Rh and give the four quantum
numbers for the last electron placed in that ground state atom.
17. (a) Describe the similarities and differences between a 2s and a 3s orbital. (b) What are the
similarities and differences between a 2s and a 2px orbital? (c) Which orbital is highest in
energy, 2s, 2px or 3s?
18. Which of the following atoms contain one or more unpaired electrons, Cd, Ge, Pt, Sr, Kr?
19. Describe why electrons must obey Hund’s Rule when they are placed in a sublevel with
degenerate orbitals.
20. (Challenge Problem) -- Calculate the energy, frequency and wavelength of the photon emitted
when an electron in hydrogen moves from n = 5 to n = 2.
Answers to Multiple Choice Problems
1.
A
2.
B
3.
C
4.
E
5.
E
6.
A
7.
D
8.
D
9.
A
10.
B
11.
D
12.
A
13.
D
14.
B
Answers to Problems 15-19
15.
16.
Br:
[Ar] 4s23d104p5
Co:
[Ar] 4s23d7
4d
↑↓
↑(↓)
↑
↑
↑
(4, 2, -1, -1/2)
a+b. Hints: Discuss shapes, relative sizes, relative energies, nodes, n and l numbers
c.
Hint: Use the periodic table to determine the order in which the orbitals are
filled. In terms of filling order, which sublevel must be the highest energy?
17.
18.
Just Ge (2 unpaired). Pt is an Aufbau exception. Do you see why it might fill its 4dsublevel?
19.
It’s the “Spread ‘Em Out Rule.” Check your notes and make sure you understand
the notes and can explain the physical reason why the electrons are spread out.