The number of molecules or ions from the following, which do not have odd number of electrons are ___________.
(A)
(B)
(C)
(D)
(E)
(F)
(A)
(B)
(C)
(D)
(E)
(F)
Show answer and solution
Answer: 03
Solution
Count total electrons for each:
(A) NO₂: N(7) + 2O(16) = 7+16 = 23 → odd
(B) ICl₂⁻: I(53) + 2Cl(34) + 1 = 53+34+1 = 88 → even ✓
(C) BrF₃: Br(35) + 3F(27) = 35+27 = 62 → even ✓
(D) ClO₂: Cl(17) + 2O(16) = 17+16 = 33 → odd
(E) NO₂⁺: N(7) + 2O(16) − 1 = 22 → even ✓
(F) NO: N(7) + O(8) = 15 → odd
The three species with even (not odd) number of electrons are ICl₂⁻, BrF₃, and NO₂⁺, giving the answer 3.
(A) NO₂: N(7) + 2O(16) = 7+16 = 23 → odd
(B) ICl₂⁻: I(53) + 2Cl(34) + 1 = 53+34+1 = 88 → even ✓
(C) BrF₃: Br(35) + 3F(27) = 35+27 = 62 → even ✓
(D) ClO₂: Cl(17) + 2O(16) = 17+16 = 33 → odd
(E) NO₂⁺: N(7) + 2O(16) − 1 = 22 → even ✓
(F) NO: N(7) + O(8) = 15 → odd
The three species with even (not odd) number of electrons are ICl₂⁻, BrF₃, and NO₂⁺, giving the answer 3.
[JEE Main 2023 · 29 Jan · Shift 1]