1.1 Atomic Structure (Ionisation Energies)

Question 1

What is the definition of first ionisation energy?

Answer 1

Energy required to remove 1 electron from a mole of gaseous atoms to give 1 mole of gaseous ions with a charge of +1

Question 2

What type of reaction is ionisation?

Answer 2

Endothermic

Question 3

What is Hie (Enthalpy of ionisation)?

Answer 3

The amount of energy required to ionise

Question 4

What is the definition of second ionisation energy?

Answer 4

Energy required to remove 1 electron from 1 mole of gaseous +1 ions to give 1 mole of gaseous ions with a charge of +2

Question 5

What is the difference between first and second ionisation energy in terms of energy required?

Answer 5

The second ionisation requires more energy

Question 6

What effects ionisation energy?

Answer 6

P- proton number increase/decrease
A- Attraction between nucleus and outer electron increase/decreasing
D- Distance between nucleus and outer electron increase/decreasing
S- Shielding between nucleus and outer electron increase/decreasing

Question 7

Why does atomic radii decrease across periods?

Answer 7

• Proton number increases
• Shielding remains the same
• Attraction is felt more strongly so radii decreases

Question 8

Why is caesium more easily ionised than lithium?

Answer 8

• Proton number increases
• Shielding increases
• Increased distance from nucleus
• Attraction is not as strong

Question 9

What is the general rule for 1st ionisation energy?

Answer 9

• increases across a period

Question 10

Why does 1st ionisation energy increase across a period?

Answer 10

• Protons increase
• Increase in shielding is negligible
• More energy required to remove outer electron

Question 11

What exceptions are there to the first ionisation rule?

Answer 11

Groups 2-3 as removing electron p subshell has a higher energy than s subshell so it is more easily removed
Groups 5-6 electrons in sub shells now need to pair up and negative electrons repel eachother

Question 12

What is the general equation for the 1st ionisation process?

Answer 12

• X -> X^1+ + e-

Question 13

When given a successive ionisation energy how can you tell which group it is in?

Answer 13

Looking at the time before there is a large increase

Question 14

Why in successive ionisation energies is there a large leap in ionisation energies?

Answer 14

Gone down a shell so less shielding and a smaller distance between nucleus and electron so attraction is stronger and requires more energy to overcome