Question

According to VSEPR theory, a molecule with the general formula AX2E2 (A is the central atom, X is the bonded atom and E is a lone pair of electrons) has how many regions of electron density around the central atom? AX2E2 will have what kind of electronic geometry? AX2E2 will have what kind of molecular geometry?

a) 3 regions; trigonal planar; bent
b) 4 regions; tetrahedral; bent
c) 4 regions; tetrahedral; linear
d) 4 regions; tetrahedral; trigonal pyramidal

Answer 1

A molecule with the formula AX2E2 according to VSEPR theory has four regions of electron density, a tetrahedral electronic geometry, and a bent molecular geometry.

Step-by-step explanation:

According to VSEPR theory, a molecule with the general formula AX2E2 will have four regions of electron density around the central atom. This is because each lone pair and each bond counts as one region of electron density, resulting in a total of four regions for the two bonded atoms (X) and two lone pairs (E). The electronic geometry for a molecule with four regions of electron density is tetrahedral. However, due to the presence of the two lone pairs, the actual molecular geometry is bent, as the lone pairs repel the bonded atoms, leading to a bent shape rather than an entire tetrahedral shape. Thus, the correct answer is (b) 4 regions; tetrahedral; bent.