Write a short note on bond order.

1.	Write a short note on bond order.
Answer» i. According to the Lewis theory, bond order is given by the number of bonds between the two atoms in a molecule. e.g., a. In hydrogen molecule, bond order between hydrogen atoms is one as one electron pair is shared. b. In oxygen molecule, bond order between oxygen atoms is two as two electron pairs are shared. c. In acetylene molecule, bond order between two carbon atoms is three as three electron pairs are shared. ii. The isoelectronic molecules and ions have identical bond orders. e.g., a. The bond order of F₂ and \(O_2^{2-}\)is one. b. The bond order of N₂, CO and NO⁺ is 3. iii. As the bond order increases, the bond enthalpy increases and bond length decreases. iv. With the help of bond order, the stability of a molecule can be predicted. [Note : N₂ molecule has bond enthalpy of 946 kJ mol^-1. It is one of the highest for diatomic molecules.]

Answer»

i. According to the Lewis theory, bond order is given by the number of bonds between the two atoms in a molecule.

e.g.,

a. In hydrogen molecule, bond order between hydrogen atoms is one as one electron pair is shared.

b. In oxygen molecule, bond order between oxygen atoms is two as two electron pairs are shared.

c. In acetylene molecule, bond order between two carbon atoms is three as three electron pairs are shared.

ii. The isoelectronic molecules and ions have identical bond orders.

e.g.,

a. The bond order of F₂ and \(O_2^{2-}\)is one.

b. The bond order of N₂, CO and NO⁺ is 3.

iii. As the bond order increases, the bond enthalpy increases and bond length decreases.

iv. With the help of bond order, the stability of a molecule can be predicted.

[Note : N₂ molecule has bond enthalpy of 946 kJ mol^-1. It is one of the highest for diatomic molecules.]

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