Question

which statement best explains why a carbon atom can bond easily with itself and other atoms?
carbon is an organic element.
carbon always forms ionic bonds with hydrogen and oxygen.
carbon has four free electrons in its outer shell that can form covalent bonds.
carbon has the same electronegativity as nitrogen, so they easily bond.

Explanation:

Carbon has 4 valence electrons in its outer - shell. These electrons can participate in covalent bonding, allowing carbon to bond with itself (forming long chains, rings etc.) and with other atoms like hydrogen, oxygen, nitrogen etc. Being an organic element doesn't explain its bonding ability. Carbon forms covalent, not ionic bonds with hydrogen and oxygen. And carbon and nitrogen do not have the same electronegativity.

Answer:

Carbon has four free electrons in its outer shell that can form covalent bonds.