I2 (iodine) has two iodine atoms. In the lewis structure of I2, there is a single bond between the two iodine atoms, and on each iodine atom, there are three lone pairs.
Here’s how you can draw the I2 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
Since I2 has two iodine atoms, so…
Valence electrons of two iodine atoms = 7 × 2 = 14
So the total valence electrons = 14
- Second, find the total electron pairs
We have a total of 14 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 = 14 ÷ 2 = 7
- Third, determine the central atom
Here, there are only two atoms and both atoms are iodine, so we can assume any one as the central atom.
Let’s assume that the central atom is right iodine.
- And finally, draw the rough sketch
#2 Mark Lone Pairs
Here, we have a total of 7 electron pairs. And one I — I bond is already marked. So we have to only mark the remaining six electron pairs as lone pairs on the sketch.
Also remember that iodine is a period 5 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 atom is left iodine.
So for each iodine, there are three lone pairs.
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 each iodine atom, formal charge = 7 – 6 – ½ (2) = 0
Here, both iodine atoms do not have charges, so no need to mark the charges.
And in the above structure, you can see that the central atom (right iodine) forms an octet. Hence, the octet rule is satisfied.
Therefore, this structure is the stable lewis structure of I2.
Next: Acetone Lewis Structure