Question

Amongst the elements with following electronic configurations, which one of them may have the highest ionisation energy? 

(a) Ne [3s² 3p²] 

(b) Ar [3d¹⁰ 4s² 4p³] 

(c) Ne [3s² 3p¹] 

(d) Ne [3s² 3p³]

Answer 1

The correct option is: (d) Ne [3s² 3p³]

Explanation:

Among options (a), (c) and (d), option (d) has the highest ionisation energy because of extra stability associated with half-filled 3p-orbital. In option (b), the presence of 3d¹⁰ electrons offers shielding effect, as a result the 4p³ electrons do not experience much nuclear charge and hence the electrons can be removed easily.