Homolytic fission is breaking a covalent bond in such a way that each atom takes an electron from the bond to form two radicals
Heterolytic fission is breaking a covalent bond in such a way that the more electronegative atom takes both the electrons from the bonds to form a negative ion and leaving behind a positive ion
Alkanes are saturated, non-polar, straight chain or branched chains with no multiple bonds between carbon atoms.