Test: Covalent Bonding of Non Metals

Methane has its molecular formula CH₄.
It is formed by one carbon atom and four hydrogen atoms. 
Hydrogen has its valency 1 and carbon being tetravalent needs four valence electrons to acquire noble gas configuration, where it shares its 4 electrons with four hydrogen atoms.
Therefore, the valency of carbon atom in Methane (CH₄) is 4.

Covalent bonds are formed by sharing of electrons.

When 2 molecules of different electronegativity are bonded together covalently the bonding electron cloud is more attracted towards atom with higher electronegativity. So, the bond between 2 Oxygen atom is non-polar . Since, it is the only bonding in oxygen molecule Oxygen molecule is non-polar.

Compounds having lesser number of carbon atoms are gases like CH₄, C₄H₁₀ and some are liquids. Compounds having greater number of carbon atoms are solids.

Because the shared pair of electrons always stays in between two elements.