Ionisation Energy 2

Question 1

3 factors that influence ionisation energy

Answer 1

1) Size of positive nuclear charge
2) Distance of electron from nucleus (size)
3) Shielding effect by electrons in inner shells

Question 2

How does the size of nuclear charge affect IE?

Answer 2

As nuclear charge increases, attraction for outermost electron increases and more energy is required to remove an electron

Question 3

How does distance of electron from nucleus affect IE?

Answer 3

The further away the outer electrons are from the nucleus, the weaker the electrostatic attraction between the nucleus and outer electrons. This makes it easier to pull an electron from the atom, therefore decreasing IE

Question 4

How does shielding affect IE?

Answer 4

Electrons in inner shells repel electrons in outer shells & reduce effect of positive nuclear charge
Greater shielding = lower ionisation energy

Question 4

Equations for 1st 2 ionisation energies of Cl?

Answer 4

1) Cl(g) —> Cl+(g) + e-
2) Cl+(g) —> Cl2+(g) + e-

Question 5

Is ionisation exothermic or endothermic?

Answer 5

Endothermic

Question 6

Why do successive ionisation energies increase within each shell?

Answer 6

Electrons are being removed from increasingly positive ion - less repulsion amongst remaining electrons, so held more strongly by nucleus