Q11.47CP - Chemistry: Molecular Nature Of Matter And Change

Question

The sulfate ion can be represented with four S—O bonds or with two S-O and two S=O bonds. 

1. Which representation is better from the standpoint of formal charges? 
2. What is the shape of the sulfate ion, and what hybrid orbitals of S are postulated for the sigma bonding?
3. In view of the answer to part (b), what orbitals of S must be used for the pi bonds? What orbitals of O?
4. Draw a diagram to show how one atomic orbital from S and one from O overlap to form a pi bond.

Step-by-Step Solution

Answer

1. The sulphate ion can be represented by the two S-O and two S=O bonds.
2. The shape of the sulphate is tetrahedral and the hybrid orbital of S is postulated with s-orbital.
3. The orbitals used for the formation of pi-bond in sulphate ion is p-orbital.
4. The diagram between the S-atom and one O-atom to show the pi-bond:

Step 1: Bonding

Bonding may be defined as the force of attraction between two or more atoms to form a compound. The molecule can have the same atom and a different atom.

Step 2: Formal Charge

The formal charge is the charge present on the individual charge of an atom which shows the bonding of the molecule. Here the  two S-O single bonds and two S=O double bonds can fulfil the octet of the S-atom.

Step 3: Sigma Bonding

Sigma bond is the bond between the molecules which is formed by the head-on-overlapping of the hybrid orbitals of the atoms. There are two single bonds S-atom and O-atom forming after the overlap of the s-orbital of both the atom by head-on-overlapping.

Step 4: Pi Bonding

Pi bond is the bond between the molecules which is formed by the side-on-overlapping of the hybrid orbitals of the atoms. There are two S-atom and O-atom forming after the overlap of the p-orbital of both the atom by side-ways-overlapping.