MAHARASHTRA Class 8: Distribution of Electrons in Orbits Videos | Valence Electrons and Octet Rule

When an electron is de-excited, it emits energy in the form of light (photons).

Being a noble element, helium has zero valency.

Oxygen has electronic configuration (2, 6); hence, its valency is 2.

Carbon atom shares four electrons from each hydrogen atom to complete its octet and form methane.