# How do you determine the molecular geometry of the molecule BeCl_2?

Apply, VESPER.......and we get a linear $B e C {l}_{2}$ molecule.
How many valence electron pairs surround the central beryllium atom? Beryllium forms 2 electron pairs to make $2 \times B e - C l$ bonds. VESPER suggests that the electron pairs are arranged in a way that MINIMIZES their interaction, and thus $\angle C l - B e - C l = {180}^{\circ}$; the molecule is therefore LINEAR.
Around each chlorine atom there are 4 electron pairs (the 7 native Cl electrons), and the one from beryllium involved in the $B e - C l$ bond. These electron pairs are arranged in a tetrahedral geometry, but because these are non-bonding lone pairs, here they do not influence geometry.