Question

A carbon atom has 6 electrons however, its valency is 4. This is because the carbon atom ________.

Answer 1

The answer is letter d. it has only 2 electrons in its first shell and 4 in the second shell. Basing from the electronic configuration of the carbon atom, the "s" orbital of carbon atom is completely filled leaving now the "p" orbitals partially filled. Thus in this case, carbon atom has four (4) valence electrons.