Bond order normally gives idea of stability of a molecular species. All the molecules viz. H2, Li2 and B2 have the same bond order yet they are not equally stable. Their stability order is

Question

Bond order normally gives idea of stability of a molecular species. All the molecules viz. H2, Li2 and B2 have the same bond order yet they are not equally stable. Their stability order is (A) H2 > Li2 > B2 (B) Li2 > H2 > B2 (C) Li2 > B2 > H2 (D) B2 > H2 > Li2

Tardigrade Admin · Accepted Answer

The molecular orbital configuration of the given molecules is

H_{2} = σ 1 s^{2}

(no anti-bonding electron)

L i_{2} = σ 1 s^{2} σ^{*} 1 s^{2} σ 2 s^{2}

(two anti-bonding electrons)

B_{2} = σ 1 s^{2} σ^{*} 1 s^{2} σ 2 s^{2} σ^{*} 2 s^{2} {π 2 p_{y}^{1} = π 2 p_{z}^{1}}

(4 anti-bonding electrons)
Though the bond order of all the species are same

(B . O = 1)

but stability is different. This is due to difference in the presence of no. of anti-bonding electrons.
Higher the no. of anti-bonding electron, lower is the stability, hence the correct order is

H_{2} > L i_{2} > B_{2}

Q. Bond order normally gives idea of stability of a molecular species. All the molecules viz. $H_{2}, L i_{2}$ and $B_{2}$ have the same bond order yet they are not equally stable. Their stability order is

$H_{2} > L i_{2} > B_{2}$

$L i_{2} > H_{2} > B_{2}$

$L i_{2} > B_{2} > H_{2}$

$B_{2} > H_{2} > L i_{2}$

Q. Bond order normally gives idea of stability of a molecular species. All the molecules viz.H2​,Li2​ and B2​ have the same bond order yet they are not equally stable. Their stability order is

H2​>Li2​>B2​

Li2​>H2​>B2​

Li2​>B2​>H2​

B2​>H2​>Li2​

Q. Bond order normally gives idea of stability of a molecular species. All the molecules viz. $H_{2}, L i_{2}$ and $B_{2}$ have the same bond order yet they are not equally stable. Their stability order is

$H_{2} > L i_{2} > B_{2}$

$L i_{2} > H_{2} > B_{2}$

$L i_{2} > B_{2} > H_{2}$

$B_{2} > H_{2} > L i_{2}$