Question

order of real ionisation enthalpy of third period. why is first ionisation enthalpy of S is less than P​

Answer 1

Explanation:

it is easier to remove electron from unpaired 3p

1

than from paired 3s

2

.

Reason:-

Electronic configuration of Al = 1s

2

2s

2

2p

6

3s

2

3p

1

Electronic configuration of Mg = 1s

2

2s

2

2p

6

3s

2

Al has one unpaired electron in it's highest energy orbital (3p), and Mg's highest energy orbital (3s) has the paired electrons.

It is energetically favourable for all the electrons in an orbital to be paired, which means that breaking up this pair would require more energy.