Question

Which of the following statement(s) is(are) correct?

• A. The electron affinity for sulphur is more exothermic than that for oxygen
• B. Successive ionization energies of an atom always increase
• C. First ionization energy of $As$ is greater than that of $Se$
• D. Chlorine has larger atomic size as well as electron affinity than that of fluorine

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A The electron affinity for sulphur is more exothermic than that for oxygen
B Successive ionization energies of an atom always increase
C First ionization energy of $As$ is greater than that of $Se$
D Chlorine has larger atomic size as well as electron affinity than that of fluorine

(A) The oxygen atom is smaller as compared to sulphur, so in oxygen, there is more inter-electronic repulsion than that of sulphur.

(B) Charge increases so size decreases and the number of electrons per proton also decreases, so valence shell electron gradually becomes more tightly held by the nucleus.

(C) Valance shell electron configuration of $As$ is $n{s}^{2}n{p}^3$ (half-filled stable configuration) and valence shell electron configuration of $Se$ is $n{s}^{2}n{p}^4$ (partially filled less stable configuration). $As=0.947$ MJ/mole; $Se=0.941$ MJ/mole

(D) Down the group atomic size increases. Fluorine experiences more inter electronic repulsion than that of chlorine; so fluorine has less electron affinity than that of chlorine.