When two atoms of different electronegativty values form a covalent bond does it result in polarity?

Question

or can it be atomic number, mass number, or valences?

Answer 1

Yes, it does; the more the difference in electronegativity the more polar the bond will be (hence the highly polar hydrogen bond). If the difference in electronegativity is small then the polarity may be so slight that the bond is effectively non-polar, but it will only be completely non-polar if the electronegativity is the same.

Answer 2

your additional details don't make sense. Electronegativity has little to do with mass number, and the other two only make sense if you are wondering why electronegativities values are what they are.

If you have something like HF, it is very polar because F has a high electronegativity, meaning it "really wants" one more electron, while H (with a much lower electronegativity) usually gets rid of one. Note there is not a real distinction in practice between ionic and polar, they just happen to exhibit trends. the ionic bonds (metal to nonmetal) just always have strong bonds and the electron is pulled so far to the nonmetal, making it what we call an ionic bond. you see that in HF, even though H is not a metal. in fact, HF is more polar than many ionic bonds, although Li-F would be stronger.

virtually any two atoms of different elements (atomic #) will be slightly polar in their bond, but arbitrarily can be marked nonpolar because they exhibit almost no charge.

Answer 3

It depends on the amount of difference in the electronegativity.

0.5 is an approximate borderline. Below that difference, it will be non polar. Above that difference, it will likely be polar. Th ebigger the difference, the more polar.