Question

The correct statements among the following are:

• A. Helium has the highest first I.P. in the periodic table
• B. The process $O_{\left(g\right)}^{-}+e^{-}\to O_{\left(g\right)}^{2-}$ is exothermic
• C. The electron affinities of S and P are less than that of O and N, respectively
• D. In any period, the first ionization potential of noble gas is the highest

Answer 1

Answer: (A), (D)

Helium has the highest first I.P. in the periodic table
In any period, the first ionization potential of noble gas is the highest

A) Helium has the highest first I.P. in the periodic table (2372.1 kJ/mol)
as it is the smallest inert gas. The $(I.P.{)}_1$ is highest for the noble gases in any period.
Hence, the given statement is a correct statement.
B) The process $O_{\left(g\right)}^{-}+e^{-}\to O_{\left(g\right)}^{2-}$ is endothermic in nature, energy must be supplied in order to overcome inter-electron repulsion. Hence, the given statement is an incorrect statement.
C) The electron affinity of oxygen is lower than the electron affinity of $S$ as $O$ is small in size and due to electron-electron repulsion, less energy is obtained in the formation of an anion. Hence, the statement C is incorrect.
D) In any period, the first ionization potential of noble gas is the highest, because noble gasses have the stable configuration so it requires more energy for removal of an electron. Helium has the maximum value of first ionization potential. Hence, the statement is correct.