Bonding

Question 1

What is bond energy?

Answer 1

Energy required to break a bond

Question 2

What is lattice energy?

Answer 2

Energy associated with making a solid ionic compound from its gaseous ions

Question 3

How do you calculate lattice energy?

Answer 3

Coulomb's law
E = (2.31x10^-19)(Q1Q2/r)
E = lattice energy
Q = charge
r = distance (in nm) between centers

Question 4

What are 4 characteristics of ionic compounds?

Answer 4

1. Solid at room temperature
2. Crystalline as solids
3. High melting/boiling points
4. Electrolytes in solution

Question 5

What are 3 characteristics of covalent compounds?

Answer 5

1. Can be polar
2. Don’t dissociate in water (typically?)
3. Lower melting/boiling points

Question 6

What property does the central atom always have?

Answer 6

It is the least electronegative.

Question 7

What three bonds “like” to be together?

Answer 7

C-H
C-O
N-H

Question 8

How do you determine formal charge?

Answer 8

Subtract the assigned valence electrons from the typical valence arrangement.
(Count bonds as 1 valence)
Ex. Oxygen typically has 6 and chlorine typically has 7

Question 9

Is formal charge preferred?

Where should the negative formal charge be?

Answer 9

No.

The central atom.

Question 10

What are three exceptions to the octet rule? Where are they seen?

Answer 10

1. Expanded octet (“spare room” in d sublevel)
2. Electron deficiency (B or Be)
3. Odd number of electrons (free radical, typically on nitrogen)

Question 11

How do you calculate bond energy in a covalent molecule?

Answer 11

Breaking minus Making.

Write formula, draw structures, look up energies, and subtract made from broken.

Question 12

What differences in electronegativity indicate a nonpolar covalent, polar covalent, and ionic bond?

Answer 12

0 - .3 nonpolar
.3 - 1.7 polar
1.7 - 3.3 ionic

Question 13

What is VSEPR?

Answer 13

Valence shell electron pair repulsion. It’s a theory that gives us atomic and electron pair arrangement.

Question 14

How do you label hybrid orbitals?

Answer 14

Count thing AROUND central atom. Don’t include central atom. Then go up s, sp, sp2, etc. up to sp3d2

Question 15

What is a sigma bond?

Answer 15

Single bond, can rotate about its axis.

Question 16

What is a pi bond?

Answer 16

Additional bond around sigma bond that make it rigid. (“Corn dog bond”)