According to VSEPR theory (Valence Shell Electron Pair Repulsion), the outside atoms in a simple molecule will be arranged in a way that minimizes the repulsion between the valence electron pairs of the atoms. This arrangement is determined by the number and type of electron pairs around the central atom, and leads to specific molecular geometries.

In general, the electron pairs will adopt a configuration that maximizes the distance between them, resulting in the most stable molecular structure. For example, in a molecule with four electron pairs, the tetrahedral geometry is the most stable arrangement, with the four electron pairs positioned at the corners of a tetrahedron, pointing away from each other. In a molecule with three electron pairs, the trigonal planar geometry is the most stable, with the three electron pairs positioned at the corners of an equilateral triangle, again maximizing the distance between the electron pairs.

VSEPR theory allows us to predict the molecular geometry and shape of simple molecules by considering the number and type of electron pairs around the central atom and determining the arrangement that minimizes electron pair repulsion.