Electronic configuration of carbon atom:
C6: 1s2 2s2 2p2
In the excited state, the orbital picture of carbon can be represented as:

Hence, carbon atom undergoes sp3 hybridization in CH4 molecule and takes a tetrahedral

shape

For a square planar shape, the hybridization of the central atom has to be dsp2

.
However, an atom of carbon does not have d-orbitals to undergo dsp2 hybridization. Hence,

the structure of CH4 cannot be square planar.

Moreover, with a bond angle of 90° in square planar, the stability of CH4 will be very less

because of the repulsion existing between the bond pairs. Hence, VSEPR theory also

supports a tetrahedral structure for CH4.

4.22 Explain why BeH2 molecule has a zero dipole moment although the Be–H bonds are polar.


Electronic configuration of carbon atom:
C6: 1s2 2s2 2p2
In the excited state, the orbital picture of carbon can be represented as:

Hence, carbon atom undergoes sp3 hybridization in CH4 molecule and takes a tetrahedral

shape

For a square planar shape, the hybridization of the central atom has to be dsp2

.
However, an atom of carbon does not have d-orbitals to undergo dsp2 hybridization. Hence,

the structure of CH4 cannot be square planar.

Moreover, with a bond angle of 90° in square planar, the stability of CH4 will be very less

because of the repulsion existing between the bond pairs. Hence, VSEPR theory also

supports a tetrahedral structure for CH4.