What is hybridisation? Please give an example.

Hybridization is changing of  pure atomic orbitals; their changing is in orbitals with the same spatial distribution and the same energy.There are 3 types of orbitals hybridization
dehibridizare the s and p: , sp2, sp.
Hybridization does not occur in elements with higher order numbers.

H20, NH3, CH4, have sp3 hybrids.

Orbital hybrids sp2 exist in the Eten molecule. They are located in plane, at angles of 120 º. P orbital left, by overlapping with the orbital p of the other atom C is forming the link pi. In the link C=C, C=O, the atoms are hybridized sp2.

Orbital  hybrids sp exist in the acetylene molecule, where the 2 orbitals sp are situated at an angle of 180 º.

There are hybridizations with the participation of d orbitals , found in compounds of transitional elements and halogenated compounds of elements in a state of high oxidation (PCl5, SF6). So, P has sp3d hybridization and S has sp3d2 hybridization.