Polar vs. Non-polar bonds

[Ryan Juncker 3D]

Is there a way to be able to tell for sure whether a bond (not molecule) is polar or non-polar without being able to see the electronegativity of both atoms?

[eduardomorales5]

You could compare the sizes of the two atoms and the number of protons that each atom has. Larger atoms have more orbitals and thus a greater amount of shielding electrons. The effective nuclear charge would not be as great as it would be for smaller atoms, and will be less able to pull electrons towards it, thus having a smaller electronegativity. More protons means a stronger ability to pull electrons towards it, thus having a larger electronegativity.

[Aliya Jain 2B]

You can also look at molecular geometry. Sometimes certain structures indicate polarity. For example since h2o has a bent structure, it is also a polar molecule.