How can a molecule be non polar when it consists of atoms that have different electronagativities?

Answer 1

When the bond dipoles cancel one another out. Fro example in CCl4 the bonds are polar but the molecule is non-polar (no dipole moment) as the bond dipoles all cancel out.

Answer 2

A molecule can be nonpolar if its overall shape is symmetric and the individual bond dipoles cancel each other out. This occurs when the molecule has a symmetrical distribution of charge, despite the presence of atoms with different electronegativities. Examples include carbon tetrachloride (CCl4) and methane (CH4).