Which orbital is non directional?
They are non directional because they are spherical in shape and probability of finding electrons at a particular distance from the nucleus is same in all directions.
Draw the orbital structure of Ethane
Each carbon has four half-filled orbitals in excited state since one electron is promoted from 2s to empty 2p orbital during chemical combination. Now, one 2s and three 2p orbitals undergo sp3 hybridization to form four sp3 hybrid orbitals of equivalent energy and identical shape which take tetrahedral geometry with bond angle 109.28°.
One half filled sp3 hybrid orbital of one carbon atom overlaps with half-filled sp3 orbital of another carbon atom head-to-head forming a carbon-to-carbon sigma bond. The remaining three half-filled sp3 orbitals of each carbon atom overlap with half-filled 1s orbital of six hydrogen atoms forming six carbons to hydrogen sigma bonds. Hence, all carbon to hydrogen bonds in ethane are identical with bond angle 109.28°.