Molecules with Trigonal Planar Parent Structures

Three Molecular Structures can result from the placement of atoms in a molecule with a trigonal planar Parent Structure.

• One with no unshared pairs of electrons
• One with 1 unshared pair of electrons
• One with 2 unshared pairs of electrons

A Molecular Structure describes the positions of the atoms in a molecule. The positions of unshared pairs of electrons are not considered when naming a molecular structure.

• A molecule with a trigonal planar Parent Structure and no unshared pairs of electrons has a trigonal planar Molecular Structure with bond angles of 120^o.
• A molecule with a trigonal planar Parent Structure and 1 unshared pairs of electrons has a bent Molecular Structure with a bond angle of 120^o.
• We will not consider trigonal planar Parent Structures with 2 unshared pairs because their structures consist of only 2 atoms.

Using your model kit, build a model of each of the following figures. The color of the atoms do not have to match. Use extra (unused) prongs on the central atom to represent any unshared pairs of electrons. Use a central atom with the smallest number of unused (extra) prongs.

On your report sheet answer the questions about the models.