QJEEM13Ch289e: JEE Main 2013 Chemistry - Class 11 JEEM13Ch289e Solution: Stability of the species Li 2 , and increases in the order of:

Question

Verified Solution • 2025–26 Session moderate

Stability of the species Li₂,

Li_2^−

and

Li_2^+

increases in the order of:

Accepted Answer

Li₂ =

{\sigma _{1{s^2}}}\,\,\sigma _{1{s^2}}^ * \,

{\sigma _{2{s^2}}} \,

\therefore

Bond order =

{1 \over 2}\left( {4 - 2} \right)

= 1

Li_2^+

=

{\sigma _{1{s^2}}}\,\,\sigma _{1{s^2}}^ * \,

{\sigma _{2{s^1}}} \,

\therefore

Bond order =

{1 \over 2}\left( {3 - 2} \right)

= 0.5

Li_2^-

=

{\sigma _{1{s^2}}}\,\,\sigma _{1{s^2}}^ * \,

{\sigma _{2{s^2}}} \,\,\sigma _{1{s^1}}^ * \,

\therefore

Bond order =

{1 \over 2}\left( {4 - 3} \right)

= 0.5

The bond order of

Li_2^+

and

Li_2^-

is same but

Li_2^+

is more stable than

Li_2^-

because

Li_2^+

is smaller in size and has 2 electrons in antibonding orbitals whereas

Li_2^-

has 3 electrons in antibonding orbitals. Hence

Li_2^+

is more stable than

Li_2^-

.

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