Question
Why is the electron gain enthalpy of $$O$$ or $$F$$ less than that of $$S$$ or $$Cl?$$
A.
$$O$$ and $$F$$ are more electronegative than $$S$$ and $$Cl.$$
B.
When an electron is added to $$O$$ or $$F,$$ it goes to a smaller $$\left( {n = 2} \right)$$ level and suffers more repulsion than the electron in $$S$$ or $$Cl$$ in larger level $$\left( {n = 3} \right).$$
C.
Adding an electron to $$3p$$ -orbital leads to more repulsion than $$2p$$ -orbital.
D.
Electron gain enthalpy depends upon the electron affinity of the atom.
Answer :
When an electron is added to $$O$$ or $$F,$$ it goes to a smaller $$\left( {n = 2} \right)$$ level and suffers more repulsion than the electron in $$S$$ or $$Cl$$ in larger level $$\left( {n = 3} \right).$$
Solution :
There is more repulsion for the incoming electron when the size of atom is smaller.