Classify the molecule SiBr4

1. polar molecule with nonpolar bonds
2. nonpolar molecule with nonpolar bonds
3. nonpolar molecule with polar bonds
4. polar molecule with polar bonds

The answer is (3), since the Si forms a tetrahedral arrangement, so there is no dipole. However, due to electronegativity differences, each bond will be polar.

2 The is the same as C Cl4 carbon tetrachloride,
It is a symetrical molecule since the outer atoms are all the same.
Silicon has 4 outer electrons it can share as 4 covalent bonds.
It's shape would be a regular tetrhedron.