Question

The number of molecules or ions from the following, which do not have odd number of electrons are ______.
(A) NO₂
(B) ICI₄^- 
(C) BrF₃ 
(D) CIO₂ 
(E) NO₂²⁺ 
(F) NO

Hint:

For identifying odd-electron species:
• Calculate the total number of valence electrons, considering charges on ions.
• Species with an odd total number of electrons will have unpaired electrons.

Answer 1

Correct Answer: 3

To determine the molecules or ions that do not have an odd number of electrons, we need to calculate the total number of electrons in each species and check if it's even.

Steps:

• (A) NO₂: N (7 electrons) + 2 × O (2 × 8 electrons) = 7 + 16 = 23 (Odd)
• (B) ICl₄^-: I (53 electrons) + 4 × Cl (4 × 17 electrons) + 1 extra (from charge) = 53 + 68 + 1 = 122 (Even)
• (C) BrF₃: Br (35 electrons) + 3 × F (3 × 9 electrons) = 35 + 27 = 62 (Even)
• (D) ClO₂: Cl (17 electrons) + 2 × O (2 × 8 electrons) = 17 + 16 = 33 (Odd)
• (E) NO₂²⁺: N (7 electrons) + 2 × O (2 × 8 electrons) - 2 (due to charge) = 23 - 2 = 21 (Odd)
• (F) NO: N (7 electrons) + O (8 electrons) = 15 (Odd)

The molecules/ions with an even number of electrons are ICl₄^- and BrF₃.

Conclusion:

The total number of species without an odd number of electrons is 2. However, this does not directly fit the expected range. Re-evaluate question inputs or expected results if needed.