Ionisation Energy

Question 1

Why is there a large jump in ionisation energy ?

Answer 1

• because once finish removing all e- in one orbital, it jumps to the next orbital that is closer to nucleus which requires more energy as a larger nuclear attraction e.g. 1st to 2nd need more IE for the 2nd

Question 2

What elements deviates from the period 3 trend ?

Answer 2

Aluminium and sulphur

Question 3

Why does aluminium deviates from period 3 trend ?

Answer 3

• it needs less energy to remove e- in 3p orbital
  Because 3p has higher energy level, and it is shielded by 3s orbital so 3p is further away from nucleus = less attraction

Question 4

Why does sulphur deviates from period 3 trend ?

Answer 4

• less energy is needed to remove shared e-
  Because sulphur has 4 e- in 3p sub shell, two electrons share the same orbital which they repel each other

Question 5

General trend of IE of period 3

Answer 5

• IE increases
• as more charge across period, but no change in shielding so more energy needed to remove outer electron as greater nuclear attraction

Question 6

Trend in IE of group 2

Answer 6

• IE decrease
• as more shielding as atom gets bigger so outer electrons more far away from nucleus so less attraction so takes less energy to remove outer e-

Question 7

Identify the element and explain from C to F has largest atomic radius ? (3)

Answer 7

M1 carbon
M2 C has same shielding as going across C to F
M3 C has less protons so smallest nuclear charge

Question 8

Identify and explain why the element in period 2 that has the highest second IE (3)

Answer 8

• lithium
• because removing one e- from the 1st IE turns it into Is2
• has no shielding effect which is very close to nucleus so a very strong attraction
• need more energy to overcome