Which of the following species has highest bond energy ?

Options

A. `O _ 2 ^( 2 - ) `
B. ` O _ 2 ^( + ) `
C. `O _ 2 ^( - ) `
D. ` O _ 2 `

Answer

A

Explanation

(a) ` O_2^ (2-) =KK' sigma 2 s^ 2 , overset(**)sigma 2s^ 2 , sigma 2p_z^ 2, pi 2p_x^ 2 ,pi 2p _y ^ 2 , overset(**)pi 2p_x^ 2,overset(**)pi 2p_y^ 2 `
Bond order ` = ( N _ b - N _ a ) /( 2 ) = ( 8 - 6 ) /( 2 ) = 1 `
(b) `O_2^+ =KK' sigma 2s^ 2 , overset(**)sigma 2s ^ 2 , sigma 2p_z^ 2, pi 2p_x^ 2 ~~pi 2p_y^2,overset(**)pi 2p_x^1 `
Bond order = ` ( 8 - 3 ) / ( 2 ) = 2. 5 `
(c) `O_2^- = KK' sigma 2s^ 2 , overset(**)sigma 2s^ 2, sigma 2p_z^2, pi2p_x^ 2~~pi 2p_y^2 overset(**)pi 2p_x^2 ~~ overset(**) pi 2p_y^ 1 `
Bond order = ` ( 8-5)/(2) = 1.5 `
(d) ` O _ 2 = KK'sigma 2s^ 2 , overset(**)sigma 2s^ 2 , sigma 2p_z^2, pi2p_x^2~~pi 2p_y^ 2 overset(**)pi 2p_x^ 1~~ overset(**)pi 2p_y^1 `
Bond order ` = ( 8 - 4 )/( 2 ) = 2 `
` because ` Bond energy ` prop ( 1 )/("Bond order") `
` therefore O _ 2 ^ (2 - ) ` has highest bond energy.