22.1 - Lattice Enthalpy

Question 1

Why are solid ionic compounds stable?

Answer 1

Strength of ionic bonds, and the electrostatic attraction between oppositely charged ions in the ionic lattice structure

Question 2

Lattice enthalpy

Answer 2

Energy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions

Question 3

Is lattice enthalpy endothermic or exothermic?

Answer 3

Exothermic
Energy change is always negative

Question 4

Standard enthalpy change of formation

Answer 4

Enthalpy change that takes place when one mole of compound is formed from its elements under standard conditions - with all reactants and products in their standard states

Question 5

Standard enthalpy change of atomisation

Answer 5

Enthalpy change that takes place for the formation of one mole of gaseous atoms from the element in its standard state under standard conditions

Question 6

Enthalpy change of formation

Answer 6

Always endothermic (positive)
Bonds are broken

Question 7

First ionisation energy

Answer 7

Enthalpy change required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

Question 8

Electron affinity

Answer 8

Energy to gain electrons

Question 9

First electron affinity

Answer 9

Enthalpy change that takes place when one electron is added to each atom in one mole of gaseous atoms to form one mole of gaseous 1- ions

Question 10

Is first electron affinity endothermic or exothermic?

Answer 10

Exothermic - electron is attracted to the positive nucleus

Question 11

Second electron affinity

Answer 11

Endothermic
Electron is being gained by a negative ion - repels electron away