The calculation for methane shows that the carbon atom is associated with 8 electrons in the s framework. This corresponds to four shape-determining electron pairs. The coordination geometry of carbon is consequently tetrahedral. There are four bonded groups, therefore there are no lone pairs.
| Lewis structure: | |
| Central atom | carbon |
| Valence electrons on central atom | 4 |
| 4 H each contribute 1 electron: | 4 |
| Total | 8 |
|---|---|
| Divide by 2 to give electron pairs | 4 |
| 4 electron pairs: | tetrahedral for the four shape-determining electron pairs |
