Question

1. sometimes the molecular geometry and the electron geometry are the same for a molecule,

sometimes they are different. write two general rules that describe the patterns seen:
the molecular and electron geometry of a molecule are the same when...
the molecular geometry differs from the electron geometry of a molecule when...

Explanation:

Molecular geometry is about the arrangement of atoms, while electron geometry considers both bonding and non - bonding electron pairs. When there are no lone pairs on the central atom, the electron pairs are all involved in bonding. So, the repulsions that determine the geometry (electron and molecular) are the same. When there are lone pairs on the central atom, the lone pairs occupy space and cause different repulsion patterns compared to bonding pairs. This leads to a difference between electron geometry (which accounts for all electron pairs) and molecular geometry (which only considers atom - atom connections).

Answer:

The Molecular and Electron geometry of a molecule are the same when there are no lone pairs of electrons on the central atom.
The Molecular geometry differs from the Electron geometry of a molecule when there are lone pairs of electrons on the central atom.