CH4 (methane) has one carbon atom and four hydrogen atoms. In the lewis structure of CH4, there are four single bonds around the carbon atom, with four hydrogen atoms attached to it, and none of the atoms has a lone pair.
Here’s how you can draw the CH4 lewis structure step by step.
Step #1: draw sketch
Step #2: mark lone pairs (if there are)
Let’s break down each step in detail.
#1 Draw Sketch
- First, determine the total number of valence electrons
Hence, carbon has four valence electrons and hydrogen has one valence electron.
Since CH4 has one carbon atom and four hydrogen atoms, so…
Valence electrons of one carbon atom = 4 × 1 = 4
Valence electrons of four hydrogen atoms = 1 × 4 = 4
And the total valence electrons = 4 + 4 = 8
- Second, find the total electron pairs
We have a total of 8 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 = 8 ÷ 2 = 4
- Third, determine the central atom
Here hydrogen can not be the central atom. Because the central atom is bonded with at least two other atoms, and hydrogen has only one electron in its last shell, so it can not make more than one bond.
Hence, here we have to assume that the central atom is carbon.
Therefore, place carbon in the center and hydrogens on either side.
- And finally, draw the rough sketch
#2 Mark Lone Pairs
Here, we have a total of 4 electron pairs. And four C — H bonds are already marked. So we do not have to mark any electron pair as a lone pair on the sketch.
And in the above structure, you can see that the central atom (carbon) forms an octet. Hence, the octet rule is satisfied.
Therefore, this structure is the stable lewis structure of CH4.
Next: BF3 Lewis Structure