Structure 2.1: The Ionic Model

Question 1

When metal atoms lose electrons,

Answer 1

They form positive cations

Question 2

When metal atoms gain electrons,

Answer 2

They form negative anions

Question 3

What is an ionic bond?

Answer 3

Electrostatic attraction between oppositely charged ions

Question 4

What is electronegativity?

Answer 4

Measure of the ability of an atom to attract a pair of electrons

Question 5

What difference of EN values will tell us it is an ionic compound?

Answer 5

1.8 or more

Question 6

What is lattice enthalpy?

Answer 6

Enthalpy change when 1 mole of an ionic lattice is broken into its gaseous ions under standard conditions

Question 7

What happens to lattice enthalpy when the ionic radius increases? (3)

Answer 7

Decreases with increasing ionic radius (1) As ionic size increases, there is a weaker electrostatic attraction between the ions (1) and so lattice enthalpy will be less endothermic (1)

Question 8

What happens to lattice enthalpy when ionic charge increases? (3)

Answer 8

Increases with increasing ionic charge (1) As ionic charge increases, there is a stronger electrostatic attraction between the ions (1), resulting in a more endothermic lattice enthalpy, and a higher MP

Question 9

Explain why ionic compounds have high melting point and boiling points

Answer 9

High electrostatic forces of attraction between the oppositely charged ions

Question 10

Why can ionic compounds dissolve in water?

Answer 10

Water is a polar solvent, and so it has partial charges. The partial charges in the water molecules attract the oppositely charged cations and anions in the ionic compound

Question 11

Electrical conductivity in ionic structures

Answer 11

Good conductivity when molten (mobile ions/delocalised electrons) Bad conductivity in solid (ions not mobile)