Question

please explain the molecular structure of ethene with respect to pi and sigma bonds...

Answer 1

Molecule of ethene has one sigma and one pi bond.
There is an axial overlapping results in formation of sigma bond.
It also has a lateral overlapping results in formation of pi bond.

Answer 2

helloo!!

 A sigma bond (σ bond) is a bond formed by the overlap of orbitals in an end-to-end fashion, with the electron density concentrated between the nuclei of the bonding atoms. 

A pi bond (π bond) is a bond formed by the overlap of orbitals in a side-by-side fashion with the electron density concentrated above and below the plane of the nuclei of the bonding 

Here ETHENE (C2H4)

means two carbons are bonded with four hydrogen
and Since, 7, one bond between C and C. And 3 bonds between one C and three H. And 3 bonds between another C and three H.

hope it helps