(N/A) The shapes of molecules can be predicted using the $VSEPR$ theory. According to this theory,molecules are classified based on the presence of lone pairs on the central atom. For molecules where the central atom $A$ is surrounded only by bonding electron pairs (with no lone pairs),the shapes are determined by the arrangement of these pairs to minimize repulsion. The following table summarizes these shapes:
| Number of electron pairs | Arrangement of electron pairs | Molecular Geometry | Hybridization | Examples |
| :--- | :--- | :--- | :--- | :--- |
| $2$ | Linear | Linear $(AB_2)$ | $sp$ | $BeCl_2, HgCl_2$ |
| $3$ | Trigonal planar | Trigonal planar $(AB_3)$ | $sp^2$ | $BF_3$ |
| $4$ | Tetrahedral | Tetrahedral $(AB_4)$ | $sp^3$ | $CH_4, NH_4^+$ |