Consider a bent molecule, such as H2Se, in which the central atom has two lone pairs of electrons. The electronegativities of H and Se are 2.1 and 2.4, respectively. Based on these values and on consideration of molecular geometry, the H-Se bond can be considered almost and the molecule is .

Based on these values and on consideration of molecular geometry, the H-Se bond can be considered almost non-polar___ and the molecule is __polar.

Explanation:

Looking at the difference in electro negativity of the two elements; hydrogen and selenium, one may be led to the conclusion that the molecule is nonpolar since the magnitude of electronegative between the two bonding atoms is minimal.

However, electro negativity difference alone is insufficient to determine the polarity of a molecule. The structure of the molecule is also considered. Based on the structure of the molecule, it is expected to have a dipole moment. Hence the molecule is polar.