Question

Which of the following is the incorrect statement?

• A. The first ionisation potential of Al is lesser than the first ionisation potential of Mg
• B. Atomic radius of Li is more than that of Cs
• C. The formation of $S^{2-}$ from $S^{-}$ is an exothermic process
• D. All of these are in correct statements

Answer 1

The correct option is D All of these are in correct statements

• Ionisation potential increases from left to right across a period. Therefore ionisation potential of Al is more than magnesium. Option A is incorrect.
• Atomic radii increases down the group as new shells are added. Therefore, atomic radii of Cs is more than Li. Option B is incorrect.
• $S^{2-}$ is more stable than $S^{-}$ so there is a lot of energy required to form unstable ions. So it is an endothermic process (Refer to image). Option C is incorrect.
• All the given statements are incorrect.