TeBr4 (tellurium tetrabromide) has one tellurium atom and four bromine atoms.
In the lewis structure of TeBr4, there are four single bonds around the tellurium atom, with four bromine atoms attached to it. Each bromine atom has three lone pairs, and the tellurium atom has one lone pair.
Here’s how you can draw the TeBr4 lewis structure step by step.
Step #1: draw sketch
Step #2: mark lone pairs
Step #3: mark charges (if there are)
Let’s break down each step in detail.
#1 Draw Sketch
- First, determine the total number of valence electrons
In the periodic table, tellurium lies in group 16, and bromine lies in group 17.
Hence, tellurium has six valence electrons and bromine has seven valence electrons.
Since TeBr4 has one tellurium atom and four bromine atoms, so…
Valence electrons of one tellurium atom = 6 × 1 = 6
Valence electrons of four bromine atoms = 7 × 4 = 28
And the total valence electrons = 6 + 28 = 34
Learn how to find: Tellurium Valence Electrons and Bromine Valence Electrons
- Second, find the total electron pairs
We have a total of 34 valence electrons. And when we divide this value by two, we get the value of total electron pairs.
Total electron pairs = total valence electrons ÷ 2
So the total electron pairs = 34 ÷ 2 = 17
- Third, determine the central atom
We have to place the least electronegative atom at the center.
Since tellurium is less electronegative than bromine, assume that the central atom is tellurium.
Therefore, place tellurium in the center and bromines on either side.
- And finally, draw the rough sketch
#2 Mark Lone Pairs
Here, we have a total of 17 electron pairs. And four Te — Br bonds are already marked. So we have to only mark the remaining thirteen electron pairs as lone pairs on the sketch.
Also remember that tellurium is a period 5 element, so it can keep more than 8 electrons in its last shell. And bromine is a period 4 element, so it can keep more than 8 electrons in its last shell.
Always start to mark the lone pairs from outside atoms. Here, the outside atoms are bromines.
So for each bromine, there are three lone pairs, and for tellurium, there is one lone pair.
Mark the lone pairs on the sketch as follows:
#3 Mark Charges
Use the following formula to calculate the formal charges on atoms:
Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons
For tellurium atom, formal charge = 6 – 2 – ½ (8) = 0
For each bromine atom, formal charge = 7 – 6 – ½ (2) = 0
Here, both tellurium and bromine atoms do not have charges, so no need to mark the charges.
In the above structure, you can see that the central atom (tellurium) forms an octet. And the outside atoms (bromines) also form an octet. Hence, the octet rule is satisfied.
Therefore, this structure is the stable lewis structure of TeBr4.
Next: AsF5 Lewis Structure