Question

Why is electron gain enthalphy of Si greater than that of phosphurus .​

Answer 1

Explanation:

If we examine the electron configuration of both the elements

P = 1S2; 2S2 2P6; 3S2 3P3

S = 1S2; 2S2 2P6; 3S2 3P4

we see that Phosphorus (P) has half filled p orbital while Sulphur (S) has partially filled p orbital.

As we know that half filled and full filled orbitals has higher stability as compared to partially filled orbitals. Hence Phosphorus is more stable than Sulphur, which makes it harder to extract an electron from Phosphorus and hence first ionization enthalpy of Phosphorus is higher than that of the Sulphur.