Answer:
The most important resonance structure is 4 (attached picture). Its bon order is or
.
Explanation:
A picture with 4 forms of the perchlorate structure is attached. The first structure has simple bonds. The second structure contains a double bond, the third structure has two double bonds and the fourth structure has three double bonds.
Formal charge = group number of the periodic table - number of bonds (number of bonding electrons / 2) - number of non-shared electrons (lone pairs)
The formal charges in the first structure is +3 in chlorine and -1 in oxygen.
The formal charges in the second structure is +2 in chlorine, -1 in oxygen and 0 in the double bond oxygen.
The formal charges in the third structure is +1 in chlorine, -1 in the single bond oxygens and 0 in the double bond oxygens.
The formal charges in the fourth structure is 0 in chlorine, -1 in the single bond oxygen and 0 in the double bond oxygens.
The most important resonance structure is given by:
- Most atoms have 0 formal charge.
- Lowest magnitude of formal charges.
- If there is a negative formal charge, it's on the most electronegative atom.
Hence, the fourth structure is the mosr important.
The bond order of the structure is:
Total number of bonds: 7
Total number of bond groups: 4
Bond order=
