Question

3. a) Define ‘first ionisation enthalpy’.


b) The table below shows successive ionisation energies of an element


Ionisation energy/kJmol-1

1st 2nd 3rd 4th 5th 6th

577 1816 2744 11577 14842 18379


Use the data to identify which group this element belongs to, explain your answer.

Answer 1

3.a. The first ionisation enthalpy is the energy required to remove one mole of the most loosely held electrons from one mole of gaseous atoms to produce 1 mole of gaseous ions each with a charge of 1+.

b. 1st- group 1

2nd- group 2

3rd - group 3

4th- group 4

5th- group 5

6th - group 6