Explain why `BeF_(2)`, molecule has zero dipolemoment although the Be-F bonds are polar.

Explanation

In `BeF_(2)` molecule the Be-F bonds have dipolemoment due to the difference in the electronegativities of beryllium and fluorine.

But in polytomic molecules the dipolemoment of a molecule is the vector sum of the dipolemoments of various bonds.
In the case of `BeF_(2)` the dipolemoment becomes zero because the two equal bond dipoles point in opposite direction and cancel effect each other.