Chapter 3: Bonding and Chemical Interactions

Question 1

Name some elements that can have an incomplete octet - elements that are stable with fewer than eight electrons in their valence shell

Answer 1

1. hydrogen (stable with 2 electrons),
2. helium (2),
3. lithium (2),
4. beryllium (4)
5. boron (6)

Question 2

Name some elements that can have an expanded octet

Answer 2

Any element in period 3 and greater can hold more than eight electrons

1. phosphorus (10),
2. sulfur (12),
3. chlorine (14), and many others.

Question 3

Name some elements that almost always abide by the octet rule

Answer 3

1. Carbon
2. Nitrogen
3. Oxygen
4. Fluorine
5. Phosphorous
6. Sodium
7. Magnesium

Question 4

Ionic bonding

Answer 4

One or more electrons from an atom with a low ionization energy, typically a metal, are transferred to an atom with a high electron affinity, typically a
nonmetal.

Question 5

Covalent bonding

Answer 5

An electron pair is shared between two atoms, typically non-metals, that have relatively similar values of electronegativity.

Question 6

Covalent bond characteristics

Answer 6

1. Bond length - the average distance between the two nuclei of atoms in a bond. (More sharing-more together)
2. Bond energy - the energy required to break a bond by separating its components into their isolated, gaseous atomic states. (More sharing-more E to break bond)
3. Polarity - occurs when two atoms have a relative difference in electronegativities.

Question 7

Non-polar covalent bond

Answer 7

• Occurs when atoms sharing electrons have identical or nearly identical electronegativities.
• Have equal distribution of charges.

Question 8

Polar covalent bond

Answer 8

• Occurs when atoms that differ moderately in their electronegativities will share electrons unevenly.
• Diff in electronegativities is between 0.5-1.7)
• Creates partial charges ( - & + )

Question 9

Coordinate covalent bond

Answer 9

Both of the shared electrons originated on the same atom.

Question 10

State the guidelines using formal charge to assess the stability of resonance structures

Answer 10

1. A Lewis structure with small or no formal charges is preferred over a Lewis structure with large formal charges
2. A Lewis structure with less separation between opposite charges is preferred over a Lewis structure with a large separation of opposite charges
3. A Lewis structure in which negative formal charges are placed on more electronegative atoms is more stable than one in which the negative formal
   charges are placed on less electronegative atoms.

Question 11

Electronic geometry

Answer 11

Describes the spatial arrangement of all pairs of electrons around the central atom, including both the bonding and the lone pairs.

Question 12

Molecular geometry

Answer 12

Describes the spatial arrangement of only the bonding pairs of electrons.

Question 13

Crystalline lattices

Answer 13

Large, organized arrays of ions.

Question 14

Formal charges

Answer 14

Exist when an atom is surrounded by more or fewer valence electrons than it has in its neutral state (assuming equal sharing of electrons
in a bond).

Question 15

Electronic geometry

Answer 15

Refers to the position of all electrons in a molecule,

whether bonding or nonbonding.

Question 16

Molecular geometry

Answer 16

Refers to the position of only the bonding pairs of electrons in a molecule.

Question 17

Sigma bonds are the result of what kind of electron density overlap?

Answer 17

Head to head overlap.

Question 18

Pi bonds are the result of what kind of electron density overlap?

Answer 18

Parallel electron cloud densities.