Bond order


first of all determine the lewis structure of nitrate NO3-

to check its lewis structure follow this link

now count the total number of bonds in the structure

there is a double between first oxygen and nitrogen atom , a single bond between second oxygen and nitrogen and another single bond between third oxygen and nitrogen

total   number of bonds are ;  2 + 1 + 1= 4

count the number of bond between the individual atoms, check this image

so the number of bonds between individual atoms are 3, so to find the bond order simply divide the number of bonds betweeen the individual atoms by the total number of bonds

4/ 3 = 1.33  the bond order