Topic 3 Test

Question 1

What types of substances usually join together to form ionic compounds?

Answer 1

Metal and non metal

Question 2

Describe ionic bonding

Answer 2

It is an electrostatic force of attraction between oppositely charged ions

Question 3

What can be said about the strength of ionic bonds?

Answer 3

They are strong

Question 4

Why do atoms gain or lose electrons?

Answer 4

They are more stable with a full outer shell of electrons i.e. the electron arrangement of a noble gas.
This is known as the Octet Rule of Thumb – when forming compounds atoms tend to have a stable electron arrangement like a noble gas with 8 electrons in the outer shell.

Question 5

What always happens when metal atoms form ions?

e.g. write an equation to show how metal ions are formed from metal atoms, Na, Mg, Al

Answer 5

They lose electrons to form positive ions.
Na Na3+ + e-
Mg Mg2+ + 2e-
Al Al3+ + 3e-

Question 6

How do you work out how many electrons a metal loses when it forms an ion?
Why do metal ions do this?

Answer 6

A metal loses electrons equal to the number of electrons in the outer shell.
They are more stable with a full outer shell of electrons.

Question 7

What happens to non-metal atoms when they form ions?

i.e. write an equation to show how non-metal ions are formed from non-metal atoms, Cl, O, N

Answer 7

They always gain electrons to become negative ions.
Cl2 + 2e- 2Cl-

O2 + 4e- 2O2-

N2 + 6e- 2N3-

Question 8

What type of substances have metallic bonding?

Answer 8

Metals

Question 9

Metallic bonding is very strong

Answer 9

.

Question 10

What type of elements usually form covalent compounds?

Answer 10

Non metals

Question 11

What is a covalent bond?

Answer 11

A shared pair of electrons

Question 12

Electrons hold covalent bonds together

Answer 12

.

Question 13

For the 4 shape molecule and 5 shape molecule what are they’re names

Answer 13

Pyramidal for 4

Tetrahedral for 5

Question 14

What type of bonding is found in a molecule

Answer 14

Covalent

Question 15

Know that the molecules bonds are strong but the bonds between molecules are weak

Answer 15

.

Question 16

What is a covalent network

Answer 16

A giant structure of covalent bonds

Question 17

Name 2 compounds with a covalent network structure

Answer 17

Silicon carbide silicon dioxide

Question 18

Why do covalent compounds not carry electricity

Answer 18

They have no charged particles to do so

Question 19

Why do Ionic bonding conduct when as a liquid or molten state but not solid

Answer 19

The ions are free to move when molten or dissolved but they are not free to move when solid as they are held in a lattice structure.

Question 20

Properties of ionic compounds

Answer 20

High melting and boiling points - Ionic bonds are very strong - a lot of energy is needed to break them. So ionic compounds have high melting and boiling points.
Conductive when liquid - Ions are charged particles, but ionic compounds can only conduct electricity if their ions are free to move. Ionic compounds do not conduct electricity when they are solid - only when dissolved in water or melted.

Eg sodium chloride

Question 21

Properties of metallic compounds

Answer 21

Very strong melting point due to strong bonds which are hard to break.
Delocalised electrons which help carry current

Question 22

Properties of covalent compounds

Answer 22

Poor conductors of electricity because no charges particles or delocalise electrons
and low melting and boiling due to weak bonds

Question 23

Properties of magnesium

Answer 23

High melting and boiling point

Flammable as it burns in air

Question 24

Network and lattice have high melt points

Answer 24

.