- Home
- Standard 11
- Chemistry
Among the following molecules / ions $C_2^{2-} ,N_2^{2-} ,O_2^{2-},O_2$ which one is diamagnetic and has the shortest bond length ?
$O_2^{2-}$
$C_2^{2-}$
$O_2$
$N_2^{2-}$
Solution
$C_2^{2 – } – {\sigma _{1s}}2{\sigma ^*}_{1s}2{\sigma _{2s}}2{\sigma ^*}_{2{s^2}}[{\pi _{2p_x^2}} = {\pi _2}p_y^2]{\sigma _{2p_z^2}}$
$B.O = \frac{{10 – 4}}{2} = 3$ (diamagnetic)
$N_2^{2 – } – {\sigma _{1s}}2{\sigma ^*}_{1s}2{\sigma _{2s}}2{\sigma ^*}_{2{s^2}}[{\pi _{2p_x^2}} = {\pi _2}p_y^2]{\sigma _{2p_z^2}}[{\pi _{2p_x^1}} = {\pi ^*}_{2p_y^1}]$
$B.O = \frac{{10 – 6}}{2} = 2$ (paramagnetic)
$O_2^{2 – } – {\sigma _{1s}}2{\sigma ^*}_{1s}2{\sigma _{2s}}2{\sigma ^*}_{2s}2{\sigma _{2p_z^2}}[{\pi _{2p_x^2}} = {\pi _2}p_y^2]\,[{\pi _{2p_x^2}} = {\pi ^*}_2p_y^2]$
$B.O = \frac{{10 – 8}}{2} = 1$ (diamagnetic)
${O_2} – {\sigma _{1s}}2{\sigma ^*}_{1s}2{\sigma _{2s}}2{\sigma ^*}_{2s}2{\sigma _{2p_z^2}}\,[{\pi _{2p_x^2}} = {\pi _2}p_y^2]\,[{\pi _{2p_x^2}} = {\pi ^*}_2p_y^2]$
$B.O = \frac{{10 – 6}}{2} = 2$ (paramagnetic)
