FINAL - SECTION 3

Question 1

Ionic bond

Answer 1

Electrons TRANSFERRED from 1 atom to another (nonmetal + metal)

Question 2

Covalent bond

Answer 2

Electrons SHARED between atoms (nonmetal +nonmetal)

Question 3

Lewis symbol

Answer 3

Dots around symbol representing valence electrons

Question 4

Octet rule

Answer 4

Tendency for atoms to want 8 electrons in outer shell

Question 5

Duet rule

Answer 5

H and He can only have up to 2 electrons in valence

Question 6

Single bond

Answer 6

Represents 2 electrons

Question 7

Double bond

Answer 7

Represents 4 electrons

Question 8

Nonpolar covalent bond

Answer 8

Electrons shared EQUALLY between atoms of bond and NO separation of charge

Question 9

Polar covalent bond

Answer 9

Electrons shared UNEQUALLY between atoms of bond and has separation of charge (S-/S+)

Question 10

Nonpolar molecule

Answer 10

Symmetric with no unshared electrons

Question 11

Polar molecule

Answer 11

Asymmetric and contain LP on central atom

Question 12

Electronegativity

Answer 12

Measures pull of electrons

Question 13

What does a high electronegativity mean

Answer 13

It means that it is stronger (greater pull of electrons)

Question 14

Electronegativity trend

Answer 14

Increase left to right and decrease top to bottom (fluorine greatest)

Question 15

How is the electronegative atom described

Answer 15

S-

Question 16

Electronegativity arrows

Answer 16

Arrow goes from S+ –> S-, but if arrows are opposite then they cancel out and are nonpolar

Question 17

Electronegativity trend

Answer 17

• Difference less than 0.4 = nonpolar covalent bond
• Difference between 0.4-2.0 = polar covalent bond
• Difference greater than 2.0 = ionic bond

Question 18

Formal charge

Answer 18

• Assigns charges to individual atoms
• FC = non bonding electrons - # of bonds

Question 19

Reasonance structure

Answer 19

• Structures with equal correctness
• Least FC preferred
• Only electrons and bonds move (NOT ATOMS)
• Single bond = 3 LP (6 e-)
• Double bond = 2 LP (4 e-)
• Triple bond = 1 LP (2 e-)

Question 20

If + necessary on resonance structure…

Answer 20

Should be on the least electronegative atom

Question 21

If - necessary on resonance structure….

Answer 21

Should be on the most electronegative atom

Question 22

Exceptions to octet rule

Answer 22

1. Free radicals: Molecules with unpaired electrons
2. Incomplete octet: Some atoms form 3 bonds instead of 4
3. Expanded valence: Elements in third row and below can have more than an octet