JEE Main 2021 · 26 August · evening · Single correct · +4 / −1
Chalcogen group elements are :
- (a) Se, Tb and Pu.
- (b) Se, Te and Po.
- (c) S, Te and Pm.
- (d) O, Ti and Po.
Answer and solution
Answer (b) Se, Te and Po.
Solution
Chemistry ma’am · 3 steps
Recite group 16 top to bottom, O, S, Se, Te, Po, and test every symbol in each option against it.
- Know the group. Chalcogens are the group 16 elements: oxygen (O), sulphur (S), selenium (Se), tellurium (Te) and polonium (Po), plus the synthetic livermorium (Lv). Each has the valence configuration ns²np⁴.
- Spot the impostors. Several symbols in the options look similar to group 16 symbols but belong elsewhere. Every element in the chosen option must be in group 16.
Option Elements Odd one out (a) Se, Tb, Pu Tb is terbium (lanthanide), Pu is plutonium (actinide) (b) Se, Te, Po none: all three are group 16 (c) S, Te, Pm Pm is promethium (lanthanide) (d) O, Ti, Po Ti is titanium (group 4, d-block) - So. Only option (b) has three chalcogens: selenium, tellurium and polonium.
The idea to keep. Learn group 16 as a chain: O, S, Se, Te, Po. Then a look-alike symbol such as Tb, Ti or Pm cannot slip past you, because the symbol must match exactly.
Answer from the NTA final answer key. Solution by PrepWiser.