Predict the geometry about each interior atom in acetic acid:

The atomic structure of the acetic acid is:

                        H     O

                        l       l

                H – C – C – O – H

                        l

                        H

We can see from the structure that there are 2 interior atoms, and these are all Carbon atoms.

The geometry is:

Tetrahedral on First Carbon

Trigonal Planar on Second Carbon