covalent bond Explain Electronegativity? What is the difference between a polar covalent bond and a nonpolar?

polar is like a water molecule...
The covalent bond SHARES electrons

so on a water molecule the oxygen end pulls on the electrons (it just does, because of the shape of the molecule it think.The shape of a water molecule is bent), making them slightly go towards the oxygen end.

This makes the oxygen end slightly negative, and the hydrogen end slightly positive.

The basic definition of a molar molecule is where there is an uneven distribution of electrons in a covalently bonded molecule

non polar is where the molecules in a covalent bond are pulling equally on the electrons.

Electronegativity is the tendency of an atom to gain electron to itself in a molecule

A non polar covalent bond is a molecule that has a covalent bond and doesn't have the differences of electronegativity or the differences is canceled due to the arrangement of the atom inside the molecule. for example Cl-Cl is a non-polar molecule because it does not has any electronegativity differences because it consists of only one molecule. H-Cl is a polar molecule because Cl is more electronegative thus the molecule is more negative in the Cl side. (+)H-Cl(-). It is a polar molecule.

CH4 does have electronegativity differences but the arrangements cancel the effect so it is a non-polar molecule

           H
            I
H--C--H
            I
           H

The ectronegativity is canceled due to the balance of arrangement left and right, up and down.

But if the any molecule that has  one lone-pair, it is definitely o polar molecule. If two, look at the arrangement.

You must look at the electronegativity chart to know the electronegativity of each atom.