13.1.1 - Lattice energy and Born Haber cycles

Question 1

What is the definition of lattice energy?

Answer 1

When one mole of an ionic solid is formed from gaseous ions.

Question 2

What is lattice energy a measure of?

Answer 2

The ionic bond strength

Question 3

What does the value of lattice energy depend on?

Answer 3

Magnitude of charge
Ionic radii
Lattice structure
Extent of covalent character in the bond

Question 4

How do we calculate lattice energy?

Answer 4

Using thermodynamic data e.g
Standard enthalpy of atomisation
Electron affinity
Ionisation energy

Question 5

What is the standard enthalpy of atomisation?

Answer 5

The standard enthalpy change when one mole of gaseous atoms are formed from an element in its standard state, at a stated temperature and pressure

Question 6

What is the first electron affinity?

Answer 6

The energy change when each atom in a mole of atoms in the gaseous state gains an electron to form a 1- ions.

Question 7

What is the second electron affinity?

Answer 7

The energy change when each ion in one mole of 1- ions gains an electron to form a 2- ion

Question 8

What is the equation when magnesium is atomised?

Answer 8

Mg(s) = Mg(g)