Plz explain me sp³ and sp² hybridisation? How do we come to know that a given compound issp³ or sp²hybridised?

Hybridisation

It states that atomic orbitals of slightly different energies combine to form a new set of equivalent orbitals (having the same energy and shape) known as hybrid orbitals.

These hybrid orbitals are more stable than atomic orbitals, and participate in bond formation.

• sp2

  • Involves mixing of one s orbital and two p orbitals to give three sp2 orbitals

  • Hybrid orbitals have 33.33% s and 66.64% p character.

  • Three hybrid orbitals orient themselves in a trigonal planar fashion at an angle of 120°.

  • Example: B in BCl3 undergoes sp2 hybridisation.

• sp3

  • Involves mixing of one s orbital and three p orbitals to give four sp3 orbitals

  • Hybrid orbitals have 25% s and 75% p character.

  • Four hybrid orbitals orient themselves in such a manner that each orbital is directed toward the four corners of a tetrahedron.

  • Example: C in CH4 undergoes sp3 hybridisation.

The number of sigma bonds around a central atom can give the information of type of hybridisation.

If total hybrid orbitals are 2, it is sp, 

If total hybrid orbitals are 3, it is sp², 

If total hybrid orbitals are 4, it is sp³,