Question

why does carbon have valency 2 & 4

Answer 1

Well till I know carbon has a valency of 2 and not (in one case)4 this is because carbon has 4 electrons in the outermost shell so it should lose or gain 4 electrons to become stable so then its valency becomes 4, but if carbon loses 4 electrons then that means 6 protons have to hold 2 electrons.