Question

There are four elements p, q, r and s having atomic numbers $Z-1$, $Z$, $Z+1$ and $Z+2$ respectively. If the element q is an inert gas, select the correct statements:
(i) p has most negative electron gain enthalpy in the respective period.
(ii) r is an alkali metal.
(iii) s exists in +2 oxidation state.

• A. (i) and (ii) only
• B. (ii) and (iii) only
• C. (i) and (iii) only
• D. (i), (ii) and (iii)

Answer 1

Answer: (D)

As 'q' is a noble gas, p, r and s having atomic number $Z-1$, $Z+1$ and $Z+2$ should belong to halogen, alkali metal and alkaline earth metal respectively.

As halogen has one electron less than stable noble gas configuration, it has a greater tendency to accept an additional electron forming an anion.

Alkaline earth metal having valence shell configuration $n{s}^2$ exists in $+2$ oxidation state.