AP Chemistry: Atomic Structure & Periodicity 2

Question 1

A sample of an element contains isotopes of mass 10.0 amu (20%) and 11.0 amu (80%). What is the average atomic mass?

Accepted Answer

10.8 amu

Answer

10.2 amu

Answer

10.5 amu

Answer

11.0 amu

Question 2

Which set of quantum numbers (n, l, ml, ms) is NOT allowed?

Accepted Answer

2, 2, 1, +1/2

Answer

2, 1, 0, +1/2

Answer

3, 2, -2, -1/2

Answer

1, 0, 0, -1/2

Question 3

How many electrons in a ground-state phosphorus atom (Z=15) are unpaired?

Accepted Answer

3

Answer

1

Answer

2

Answer

5

Question 4

Which species is isoelectronic with the neon atom?

Accepted Answer

Na+

Answer

Cl-

Answer

K+

Answer

Li+

Question 5

What is the maximum number of electrons that can occupy the n=3 principal energy level?

Accepted Answer

18

Answer

8

Answer

9

Answer

32

Question 6

An electron transition releasing the highest-energy photon in a hydrogen atom would be from n=4 to which level?

Accepted Answer

n=1

Answer

n=3

Answer

n=2

Answer

n=5

Question 7

Which subshell is filled immediately after the 4s subshell according to the aufbau principle?

Accepted Answer

3d

Answer

4p

Answer

5s

Answer

4d