Question

If the bond order of carbonate ion ($C{{O}_{3}}^{-2}$) is expressed by the simple ratio x:y. Then the value of (x+y) will be.

Answer 1

Hint: Bond order of polyatomic molecules can be determined using the resonating structures. Bond order can be used to determine stability and strength of the bond. A high bond order indicates more attraction of electrons.

Complete step by step answer:
Bond order is the number of chemical bonds between a pair of atoms and indicates the stability of a bond. Bond order is the number of bonding pairs of electrons between two atoms. In covalent bonds between two atoms, a single bond has a bond order of one, a double bond has a bond order of two, a triple bond has a bond order of three, and so on. If the bond order is zero, the molecule cannot form. The higher bond orders indicate greater stability for the new molecule. In molecules that have resonance bonding, the bond order does not need to be an integer.
For polyatomic molecules, bond order can be calculated by making the resonance structures. The formula for calculating through resonance structure is written as ratio of total number of bonds in the molecule and total number of resonating structures.
For carbonate ion $C{{O}_{3}}^{-2}$, the resonating structures are given as follows:

It has 3 resonating structures and total four bonds are present in one structure. The bond orders of the $C{{O}_{3}}^{-2}$ will be 1 and 3. When it is in the form of x and y, and if x=1 and y=$\dfrac{1}{3}$.
Therefore, x+y = $1+\dfrac{1}{3}=\dfrac{1+3}{3}=\dfrac{4}{3}$
Therefore, x+y=1.33 .

Note: Bond order and bond length indicate the type and strength of the covalent bond between atoms. Bond order and bond length are inversely proportional to each other, when bond order increases bond length is decreased.