Why are there polar bonds in CBr4?

You should be able to answer this without the periodic table. I ll help you. Br is a member of the halogen family along with F, Cl and I. Halogens are more electronegative as compared to Carbon. Therefore they tend to pull the electron cloud of carbon towards themselves making the bond polar. The entire compound is non-polar however. This is because all the dipole moments cancel each other out.