Question

why cant carbon gain electrons?????? in our textbookks its written dat due to energy cosiderations an element cant gain electrons wat is energy consideration here???????

Answer 1

Carbon has 4 valence electrons in its outermost shell, which is half of the total numbers electrons in the last shell, and has a 6 number of protons. If carbon gain 4 electrons to complete it's octet and became C(-4) anion then it would take lot of energy to add electrons to atom having 6 protons to attract 10 electrons and the atom will be highly unstable. If carbon loses 4 electrons to became C(+4) cation then it would take lot of energy to take out electron and forming a atom with 6 protons and two electrons only.
So to overcome this problem carbon atom share it electrons to form covalent bond.

Answer 2

Here energy consideration means the ionization energy of carbon atom and electronegativity.

Hope it helps.