Carbon atom can have three different hybridizations. In an alkene carbon is sp² hybridized forming three sigma bonds and one pi bond. While in alkynes it is sp hybridized with two sigma bonds and two pi bonds. It can be stated that if a carbon atom is bonded to four other atoms or if the number of lp+bp (steric number) is 4 it is sp3 hybridized, if the steric number is 3 it is sp2 hybridized and if it is 2, then the hybridization is sp.