Question

ii. Bi does not form pr-pπ
bonds. Give reason for the observation
i Electron gain enthalpy of oxygen is less negative than sulphur. Justify​

Answer 1

Reason is given below.

Explanation:

• We have to find why the electron gain enthalphy is less negative,this is because both of them are the elements of  16th group in which the oxygen is 1st element which has the minimum size and we know as we move downwards the size increases so sulphur has larger size which is due to addition of a new shell.
• So, it has smaller size due to which  the inter-electronic repulsion in  2p-orbitals of oxygen is much more than the repulsion in 3p-orbitals of sulphur.
• Hence, new electron which enters feels less attraction in oxygen and more attraction in sulphur due to which the addition becomes easy and so electron gain enthalpy becomes more negative in sulphur.
• EGH  = Oxygen < Sulphur, since size of sulphur is greater than oxygen.
• Since, the size of oxygen is lesser than the sulphur, so incoming e− on oxygen faces more electronic repulsion on oxygen outermost surface (which is due to more e− density) as a result electron affinity also decreases.
• So, oxygen have less negative electron gain enthalphy when compared to sulphur.