1.1.2 First ionisation

Question 1

What is first ionization energy?

Answer 1

It is the energy needed to remove one mole of electron from one mole of a gaseous atom

Question 2

What is the equation for first ionization?

Answer 2

X(g) –> X(+)(g) + e(-)

Question 3

What type of reaction is ionization?

Answer 3

Endothermic - it requires energy

Question 4

What is the trend in first ionization energy as you go down a group?

Answer 4

The first ionization energy decreases as you go down a group. This is because of shielding between the nucleus and the outer electron.

Question 5

What is the trend in first ionization energy as you go across a period?

Answer 5

It will increase as you go across a period. This is because there is a higher nuclear charge, but with similar shielding.

Question 6

What is the evidence for energy sub-levels?

Answer 6

There is a slight drop in first ionization energy as you enter a new sub-shell. This is because new sub-shells have slightly higher energy, meaning less is needed to remove an electron.