Module 9

Question 1

Bond Angle of a molecule w/:
1 central atom + 2 other atoms

Answer 1

Electron-Group Structure: Linear
180 degrees

Question 2

Bond Angle of a molecule w/:
1 central atom + 3 other atoms

Answer 2

Electron-Group Structure: Trigonal Planar
120 degrees

Question 3

Bond Angle of a molecule w/:
1 central atom + 4 other atoms

Answer 3

Electron-Group Structure: Tetrahedral
109.5 degrees

Question 4

How to find shape of molecule using VSEPR

Answer 4

1. Draw Lewis structure
2. Count groups of valence electron
3. Pick electron-group structure
4. Assign each lone pair group to place in electron group structure
5. Assign each bonding electron group to somewhere in the electron-group structure
6. Consider bonding groups and structures
   thumbs up

Question 5

Linear electron group structure

Answer 5

Angle: 180 degrees
2 electron groups
2 bonds
No lone pairs
2 ligands

Question 6

Bent electron group structure

Answer 6

Angle: 109.5
3-4 (depending on lone pairs) electron groups
1-2 lone pairs
2 bonds
2 ligands

Question 7

Trigonal planar elecron group structure

Answer 7

Angle: 120 degrees
3 electron groups
Can have lone pairs
3 bonds
3 ligands

Question 8

Trigonal pyramidal

Answer 8

Angle: 109.5 degrees
4 electron groups
1 lone pair
3 bonds
3 ligands

Question 9

Tetrahedral

Answer 9

Angle: 109.5 degrees
4 electron groups
No lone pairs
4 bonds
4 ligands

Question 10

Intermolecular Forces

Question 11

Hydrogen-bonding

Answer 11

Kind of intermolecular force btwn molecules that:
1) Have 1 of a strongly electronegative molecules O, N, F in each molecule
2) Said electronegative atom in 1 molecule must a) be chemically bonded to a hydrogen, and b) the electronegative atom in the other molecule must have >= 1 lone pair.

Question 12

Dipole-dipole force

Answer 12

An intermolecular force btwn polar molecules that attracts

Question 13

London- dispersion forces

Answer 13

An intermolecular force that any 2 molecules exert on each other that attracts

Bigger molecules experience stronger dispersion forces.

Question 14

Polarizability

Answer 14

Increases with the number of electrons in an atom/molecule
i.e. the more electrons, the better
* You can determine strength of dispersion forces w/ this

Question 15

Boiling point & Intermolecular forces

Answer 15

The stronger the intermolecular force, the higher the boiling point

Question 16

Single bond

Answer 16

1 sigma

Question 17

Double bond

Answer 17

1 sigma + 1 pi

Question 18

Triple bond

Answer 18

1 sigma + 2 pi

Question 19

sp^3 hybridization

Answer 19

4 sigma bonds + lone pairs

Question 20

sp^2 hybridization

Answer 20

3 sigma bonds + lone pairs

Question 21

sp hybridization

Answer 21

2 sigma bonds + lone pairs

Question 22

Valence Bond Theory

Question 23

Hybridization

Answer 23

Can be determined by counting sigma bonds + lone pairs

Question 24

Polar vs. Nonpolar

Answer 24

Consider shape of molecule and electronegativity of each atom.

Question 25

Trigonal Bipyramidal

Answer 25

5 electron groups
90 degrees vertical, 120 degrees horizontal

Question 26

Octahedral

Answer 26

6 electron groups
90 degrees vertical, 90 degrees horizontal

Question 27

AXE Notation

Answer 27

A - Central Atom
X - ligands
E - lone pairs on central atom

Question 28

Hybridization

Answer 28

1. Count the electron groups (include lone pairs)
2. Each one corresponds to s, p, and d orbitals
   i.e. 4 electron groups is sp^3,
   5 electron groups is sp^3d, etc.

Question 29

Causes of Deviations from Ideal Bond Angle

Answer 29

• Double, Triple bonds
• Lone pairs

Question 30

Ion-dipole

Answer 30

Ions and polar molecules exert this on each other.

Question 31

Comparing boiling points

Answer 31

1. ID which w/ strong bonding forces, i.e. metal and binary ionic compounds
2. Compare molar masses. The greater, the higher
3. W/ similar masses, ID any special intermolecular forces, i.e. dipole and intermolecular forces