Unit 5 - Chemical Bonding

Question 1

Lewis structures

Answer 1

octets cannot exceed in C, N, O, F;
adjacent atoms rarely have the same formal charge;
usually the negative charge are on the most EN atoms;
H and F are always terminal;
groups 2A and 3A can have less than 8 electrons

Question 2

Electronegativity and bonding

Answer 2

EN > 1.9 = ionic bonding;
EN 0.4 - 1.9 = polar covalent bonding;
EN < 0.04 = covalent bonding;
as the difference in electronegativity increases, the percent ionic character increases

Question 3

AX2

Answer 3

linear;

180

Question 4

AX3

Answer 4

trigonal planar;

120

Question 5

AX2E

Answer 5

bent;

< 120

Question 6

AX4

Answer 6

tetrahedral;

109

Question 7

AX3E

Answer 7

trigonal pyramid;

< 109

Question 8

AX2E2

Answer 8

bent;

&laquo_space;109

Question 9

AX5

Answer 9

trigonal bipyramid;

120, 90

Question 10

AX4E

Answer 10

seesaw;

< 120, < 90

Question 11

AX3E2

Answer 11

t-shape;

< 90

Question 12

AX2E3

Answer 12

linear;

180

Question 13

AX6

Answer 13

octahedral;

90

Question 14

AX5E

Answer 14

square pyramid;

< 90

Question 15

AX4E2

Answer 15

square planar;

90

Question 16

AX3E3

Answer 16

t-shape;

< 90

Question 17

AX2E4

Answer 17

linear;

180

Question 18

Bond order, length, and energy

Answer 18

as bond order increases, length decreases and energy increases;
as size of atom decreases, length decreases and energy increases

Question 19

Methane clathrate ice

Answer 19

molecular structure determine solubility as like dissolves in like;
therefore, it is unusual for methane to be trapped in ice because it is a non-polar substance dissolved in a polar substance;
due to increased amount of methane in the atmosphere

Question 20

Hemoglobin

Answer 20

characterized by iron, oxygen and heme unit;
O2 binds to the heme unit;
however, CO has a greater affinity since the C has a negative formal charge which interacts better with the iron