What is the Lewis structure for silicon tetra bromide?

Answer 1

SiBr4

EDIT: While the above answer is correct, that is actually the molecular formula, which is not what the question is asking. In order to determine a molecule's lewis dot structure, follow these steps:

1. Count the number of valence electrons (e-) for each atom.

Bromine 7 valence e- X 4 atoms = 28 e-

Silicone 4 valence e- X 1 atom = 4 e-

Total valence e-: 32 e-

2. Determine which atom is the central atom; draw "skeleton" of structure. Typically the central atom is either a. the only atom that occurs once in the molecule and/or b. is the atom that can form the most bonds (least number of valence e-). In this case, silicone is the only atom that occurs twice and can form the most bonds (4 bonds, as it has 4 valence e-). Join all atoms using only single bonds (single lines).

3. Add lone pairs (dots) to each atom accordingly. This is determined by subtracting the number of lines (step 2) from the total of valence e- (step 1). Each line represents a pair of electrons (2 e-). Note: if the total obtained in step 1 is the same as the number achieved in this step, you are done (notapplicable in this case). Place the dots around surrounding atoms first, then place any leftover dots on central atom (ifapplicable).

32 - 8 (4 bonds are created [4 bonds x 2 e- each = 8]) = 24 e- (24 dots to be drawn).

In this case, there will be 6 dots around each bromine atom, as 1 pair is shared with the central atom (silicone).

4. Make sure the octet rule (duet rule for hydrogen always) is represented for all elements involved in bond(s). If an atom does not have 8 e- attached (for atoms where the duet rule applies [ex. hydrogen, represented by a single line]), double or even triple bonds may be necessary to achieve the octet rule for all atoms.

In this case, all atoms have achieved the octet rule with single bonds.

According to the VSEPR model, since this molecule has 4 atoms bonded to the central and has 0 unshared e- pairs on the central atom, the molecule's geometric shape is tetrahedral, meaning the bond angles are formed at about 109.5 degrees Celsius.