Ch4 Chem Concepts

Question 1

Ionization energy

Answer 1

The energy necessary to remove an electron from a gas-phase atom or ion.

Ionization energy increases across a period. Ionization energy increases up a group.

Question 2

Electron affinity

Answer 2

The energy change that occurs when an electron is added to a gas-phase atom.

Halogens have large, negative electron affinities.
Noble gases have positive electron affinities.
Alkaline earth metals have electron affinities that are approximately equal to zero.

Question 3

Lattice energy strength

Answer 3

bigger charges lead to larger lattice energies.

bigger ions lead to smaller lattice energies.

Question 4

Electronegativity

Answer 4

the extent to which an atom attracts shared electrons.

Question 5

Bond polarity

Answer 5

the degree to which bonding electrons are transferred.

Question 6

Relative Importance of Resonance structures

Answer 6

1. each atom should satisfy the octet rule.
2. Like charges on adjacent atoms are unfavorable.
3. Smaller formal charges, either positive or negative, are preferable.
4. A more negative formal charge should reside on a more electronegative atom.

Question 7

Removing electrons from metals w/ variable charge

Answer 7

Remove from highest p subshell for first charge, then remove from s subshell for 2nd charge.

Question 8

Diamagnetic materials

Answer 8

are slightly repelled by a magnet.

All of the electrons in diamagnetic materials are paired.

Question 9

Paramagnetic materials

Answer 9

are attracted by a magnet.

Paramagnetic materials contain at least one unpaired electron.

Question 10

VB Theory

Answer 10

Atom centered, better with localized electrons, easy to visualize; good at justifying molecular shapes.

Question 11

MO Theory

Answer 11

Molecule centered, better with delocalized electrons, better at explaining energies, bond orders, and magnetic properties.