AP Chemistry: Chemical Bonding & Molecular Structure 3

Question 1

Which species is isoelectronic with the neon atom?

Accepted Answer

F-

Answer

F- gains one electron to reach 10 electrons, identical to neon's configuration.

Question 2

In molecular orbital theory, what is the bond order of the O2 molecule?

Accepted Answer

2

Answer

O2 has a bond order of 2, calculated as (8 bonding - 4 antibonding)/2.

Question 3

Why is O2 paramagnetic, a property correctly predicted by molecular orbital theory but not by simple Lewis structures?

Accepted Answer

It has two unpaired electrons in pi antibonding orbitals

Answer

MO theory places two unpaired electrons in the degenerate pi* antibonding orbitals, making O2 paramagnetic.

Question 4

Which of the following molecules is nonpolar despite containing polar bonds?

Accepted Answer

CCl4

Answer

CCl4 has tetrahedral symmetry that causes the bond dipoles to cancel, making it nonpolar.

Question 5

What type of crystal lattice is found in solid sodium chloride?

Accepted Answer

Ionic

Answer

NaCl forms an ionic lattice of alternating Na+ and Cl- ions held by electrostatic attraction.

AP Practice Test