DN 2). Shapes Of Molecules

Question 1

A covalent bond is….

Answer 1

A shared pair of electrons

Question 2

Two types of electron pairs

Answer 2

Bond pair

Lone pair

Question 3

Order of repulsion

Answer 3

Lone pair-lone pair > bond pair - lone pair > bond pair - bond pair

Question 4

Why do lone pairs repulse more than bond pairs

Answer 4

The lone pairs are clouds of negative charge
Will repel so are maximum distance apart
Bond pairs will do the same but the negative charge is spread out over a larger area
So their charge density is lower and so don’t repel as much

Question 5

Ionic melting point

Answer 5

High
Lattice
Lots of strong electrostatic attraction between opp charged ions

Question 6

Ionic conductive

Answer 6

Pint when solid
Only molten or in solution
Ions need to be free to move to carry the current

Question 7

Strength of ionic

Answer 7

Strong but brittle
Lattice
Electrostatic attraction between opp charged ions
Brittle because if distorted like charges adjacent so repulsion breaks apart

Question 8

All molecules contain which type of bonding

Answer 8

Covalent

Question 9

Ionic solubiltiy

Answer 9

Soluble.
Polar water molecules attracted to ions
surround them and make lattice break

Question 10

Simple molecular mp

Answer 10

Low.
Strong covalent bonds between atoms
Weak IMF between molecules

Question 11

Simple molecular conductivity

Answer 11

No.

No charged particles to move to carry the current.

Question 12

Simple molecular strength

Answer 12

Not strong
Strong covalent bonds between atoms
Weak IMF between molecules

Question 13

Simple molecular solubility

Answer 13

Not in water.

No charged particles to attract the polar water molecules

Question 14

Giant covalent mp

Answer 14

High
Macromolecular structure
lots of string covalent bonds
lots of energy

Question 15

Giant covalent electrical conductivity

Answer 15

No

no charged particles to move to carry the current

Question 16

Giant covalent strength

Answer 16

strong
macromolecular structure
lots of strong covalent bonds
lots of energy to break

Question 17

Giant covalent solubility

Answer 17

No

no charged particles to attract polar water molecules

Question 18

Metallic mp

Answer 18

High
lattice of positive ions surrounded by a sea of delocalised electrons
strong electrostatic attraction between oppositely charged particles

Question 19

metallic conductivity

Answer 19

yes even when solid

electrons are free to move to carry the current

Question 20

Metallic strength

Answer 20

Strong
lattice of positive ions surrounded by a sea of delocalised electrons
strong electrostatic attraction between oppositely charged particle

Question 21

Metallic solubility

Answer 21

Insoluble

Doesn’t attract polar water molecules to disrupt the lattice

Question 22

what is ionic bonding

Answer 22

electrostatic attraction between oppositely charged ions

Question 23

what is a covalent bond

Answer 23

a shared pair of electrons

Question 24

what is metallic bonding

Answer 24

electrostatic attraction between positive ions and negative electrons

Question 25

what is a dative (or coordinate) bond and how do you draw it

Answer 25

a shared pair of electrons when both electrons come from the same atom draw it with an arrow

Question 26

is there any difference between a dative bond and a normal covalent bond

Answer 26

no

Question 27

electronegativity definition

Answer 27

the power of an atom to attract the electron density in a covalent bond towards itself

Question 28

nuclear charge....... electronegativity

Answer 28

more protons, stronger attraction between nucleus and bonding pair of electrons

Question 29

atomic radius........ electronegativity

Answer 29

closer to the nucleus, stronger attraction between nucleus and bonding pair of electrons

Question 30

shielding....... electronegativity

Answer 30

less shells of electrons between the nucleus and the electrons, less shielding (less repulsion), stronger attraction between nucleus and bonding pair of electrons

Question 31

as you go across a period electronegativity........ | Why?

Answer 31

increases +nuclear charge distance of bonding electrons from the nucleus = same shielding = same therefore bonding electrons attracted more strongly

Question 32

as you go down a group electronegativity.......... | why?

Answer 32

decreases despite + nuclear charge distance of bonding electrons from nucleus increases shielding increases therefore bonding electrons attached less strongly

Question 33

3 types of IMF (weakest to strongest)

Answer 33

van der waals...........permanent dipole-permanent dipole...........hydrogen bonding

Question 34

explain van der waals forces

Answer 34

temporary dipole - induced dipole attraction at any instance electron distribution is unsymmetrical due to the movement of electrons this creates a temporary dipole the electrons around this dipole will move causing an induced dipole.

Question 35

stronger van der waals......

Answer 35

larger molecule more electrons STRONGER van der waals (NB shape is important to do with packing)

Question 36

explain permanent dipole - permanent dipole forces

Answer 36

polar molecule the permanent dipoles attract each other (NB watch for symmetry resulting in there not actually being a dipole)

Question 37

explain hydrogen bonds

Answer 37

the strongest dipole 0 dipole force which exists between the lone pair of electrons o a NOF atom and a H atom that is d+ because it is attached to a NOF

Question 38

sulfate ion

Answer 38

SO4 2 minus

Question 39

hydroxide ion

Answer 39

OH MINUS

Question 40

nitrate ion

Answer 40

NO3 2MINUS

Question 41

carbonate ion

Answer 41

CO3 2 MINUS

Question 42

ammonium

Answer 42

NH4 PLUS

Question 43

ammonia

Answer 43

NH3