Carbon has 4 electrons in its outermost orbits and in order to attain the noble gas configuration, it should either lose or gain 4 electrons. Being a tetravalent its property is to gain or lose 4 electrons to be stable as noble gases. Carbon is Tetravalent, it does not form an ionic bond by either losing 4 electrons or by gaining 4 electrons. It always forms bonds by sharing its electrons i.e, covalent bonds.