Which of these represents the correct order of decreasing bond order?

Step-by-step solution

Bond Order = 1 2 (N_b - N_a) He₂^+ (3e): _ 1s ^2 _ 1s ^ *1 BO = 1 2 (2-1) = 0.5 O₂^- (17e): _ 1s ^2 _ 1s ^ *2 _ 2s ^2 _ 2s ^ *2 _ 2p_z ^2 _ 2p_x ^2 _ 2p_y ^2 _ 2p_x ^ *2 _ 2p_y ^ *1 BO = 1 2 (10-7) = 1.5 C₂²⁻ (14e): _ 1s ^2 _ 1s ^ *2 _ 2s ^2 _ 2s ^ *2 _ 2p_x ^2 _ 2p_y ^2 _ 2p_z ^2 BO = 1 2 (10-4) = 3.0 O₂²⁺ (14e): _ 1s ^2 _ 1s ^ *2 _ 2s ^2 _ 2s ^ *2 _ 2p_z ^2 _ 2p_x ^2 _ 2p_y ^2 BO = 1 2 (10-4) = 3.0 He₂²⁺ (2e): _ 1s ^2 BO = 1 2 (2-0) = 1.0 Decreasing order: C₂²⁻(3.0) > O₂²⁺(3.0) > O₂^-(1.5) > He₂²⁺(1.0) . Answer: