chapter 7 - covalent model

Question 1

what is a covalent bond

Answer 1

the electrostatic attraction between the positively charged nuclei of both atoms and shared pair of electrons

Question 2

what is the simplest covalent molecule

Answer 2

H2

Question 3

what is the octet rule

Answer 3

electrons shared so that the central atom has 8 electrons in the outer shell

Question 4

what is a lone pair

Answer 4

a pair of electrons in the outer shell of an atom that is not involved in covalent bonding

Question 5

how does a double covalent bond form

Answer 5

the sharing of 2 pairs of electrons

Question 6

what is bond energy

Answer 6

the energy required to break a covalent bond

Question 7

what is bond length

Answer 7

the distance between the nuclei of atoms making up a covalent bond (the length of a covalent bond)

Question 8

order of decreasing bond energy (highest to lowest)

Answer 8

triple
double
single

Question 9

are triple or double bonds longer and why

Answer 9

triple bonds are shorter due to the stronger attraction between the bonding electrons and the nuclei when there are more electrons in the bond

Question 10

what is a coordination bond

Answer 10

a type of covalent bond where the electrons come from the same atom
aka dative covalent bond

Question 11

electron domain geometry for 2 electron domains

Answer 11

linear 180

Question 12

electron domain geometry for 3 domains

Answer 12

trigonal planar 120

Question 13

electron domain geometry for 4 domains

Answer 13

tetrahedral 109.5

Question 14

order of repulsion strength for pairs of electrons

Answer 14

lone pair - lone pair> lone pair - bonding pair > bonding pair - bonding pair.

Question 15

What is electronegativity?

Answer 15

Electronegativity refers to the ability of an atom to draw electrons towards itself in a covalent bond

Question 16

weakest to strongest intermolecular forces

Answer 16

london forces
dipole dipole forces
hydrogen bonding

Question 17

are substances that can participate in hydrogen bonding soluble in water and if so why

Answer 17

yes because they can hydrogen bond to water

Question 18

how do you calculate rf value

Answer 18

distance solute moves/ distance solvent front moves

Question 19

properties of diamond

Answer 19

arranged in tetrahedral array

very high MP and BP and hard because covalent bonds must be broken when diamond is melted/boiled; requires lots of energy as the bonds are very strong.
does NOT conduct electricity(electrons held tight in covalent bond)
not soluble

Question 20

properties of graphite

Answer 20

arranged in trigonal planar array

good lubricant - london forces between layers
high MP and BP
DOES conduct electricity - extra electron from p orbital

Question 21

properties of graphene

Answer 21

a single layer of graphite

good electrical and thermal conductor
high tensile strength
high MP

Question 22

c60 fullerene properties

Answer 22

insoluble in water
does NOT conduct electricity
it is a molecular structure