Choose the pair of elements [(A) to (F)] which: (i) belong to the Chalcogen family (ii) form monovalent oxides which give alkalies in aqueous solution (iii) form stable monovalent anions (A)1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^1 (B) 1 s^2 2 s^2 2 p^5 (C) 1 s^2 2 s^2 2 p^6 3 s^1 (D) 1 ~s ^2 2 ~s ^2 2 p ^6 3 ~s ^2 3 p ^5 (E) 1 s^2 2 s^2 2 p^6 3 s^2 3 p^4 (F) 1 ~s ^2 2 ~s ^2 2 p ^4

Step-by-step solution

Identifying each element by valence configuration: A ( 4s^1 ) Group 1 (Alkali metal) B ( 2s^22p^5 ) Group 17 (Halogen) C ( 3s^1 ) Group 1 (Alkali metal) D ( 3s^23p^5 ) Group 17 (Halogen) E ( 3s^23p^4 ) Group 16 (Chalcogen) F ( 2p^4 ) Group 16 (Chalcogen) (i) Chalcogen family (Group 16): E and F (ii) Monovalent oxides giving alkalies (Group 1, ns^1 ): A and C (form Na₂O , K₂O type oxides alkaline solution) (iii) Stable monovalent anions (Group 17, need 1 electron): B and D Answer: (i) E&F, (ii) A&C, (iii) B&D