Ionisation Energies

Question 1

What is first ionisation energy?

Answer 1

First ionisation energy is the energy required to remove 1 electron from each atom in 1 mol of gaseous atom to form 1 mol of 1+ ion

Question 2

State the 1st I.E for sodium gas

Answer 2

Na (g) -> Na+ (g) + e-

Question 2

Name the 3 factors that affect I.E

Answer 2

Atomic radius
Nuclear charge
Electron shielding or screening

Question 3

What is electron shielding?

Answer 3

The repulsion between electrons in different inner shells. Shielding reduces the net attractive force from the +ve nucleus on the outer-shell electrons

Question 4

What is successive ionisation energy?

Answer 4

The measure of the energy required to remove each electron in turn.

Question 5

State the second I.E for sodium gas

Answer 5

Na+ (g) + Na2+ (g) + e-

Question 6

Magnesium has a greater I.E than Strontium. Explain why

Answer 6

Atomic radius
Electron shielding
Nuclear attraction

Magnesium has a greater I.E than strontium because it has a smaller ionic atomic radius, less electron shielding and outer electrons with stronger attractions to the nucleus