What are the Lewis structure, valence electrons, electron domains, electron domain geometry, and molecular geometry for CH4?

A. Lewis Structure for CH4

The Lewis structure of methane (CH₄) shows a central carbon atom bonded to four hydrogen atoms. Each hydrogen atom shares one pair of electrons with the carbon atom. The structure can be depicted as:

     H
     |
 H - C - H
     |
     H

B. Number of Valence Electrons

To determine the total number of valence electrons in CH₄, we add the valence electrons from each atom. Carbon has 4 valence electrons, and each hydrogen has 1 valence electron. Thus, the total is:

4 (from C) + 1*4 (from 4 H) = 8 valence electrons

C. Number of Electron Domains (Both Bonding and Nonbonding)

In CH₄, there are a total of 4 bonding electron domains (one for each C-H bond) and no nonbonding electron pairs on the carbon atom. Therefore, the total number of electron domains is:

4 bonding + 0 nonbonding = 4 electron domains

D. Electron Domain Geometry

With 4 electron domains, the electron domain geometry adopts a tetrahedral shape. This arrangement minimizes repulsion between the electron pairs.

E. Molecular Geometry

Since CH₄ has no lone pairs on the carbon atom and all domains are bonding, the molecular geometry is also tetrahedral. This is indicative of the symmetrical distribution of electrons around the central carbon atom.