Question

predict the molecular geometry of this molecule:
step 1
select the electron - pair geometry for this molecule. check your answer.
step 2
place terminal atoms in the appropriate positions on the molecule. check your answer.
step 3
enter the molecular geometry for this molecule.
molecular geometry:

Explanation:

Step1: Analyze the Lewis structure

The molecule shown is \( \ce{NF3} \) (nitrogen trifluoride). Nitrogen is the central atom. Nitrogen has 5 valence electrons, and each fluorine has 7. In \( \ce{NF3} \), nitrogen forms 3 single bonds with fluorine atoms, and there is 1 lone pair of electrons on nitrogen. So the electron - pair geometry (considering both bonding and lone pairs) is tetrahedral (since the number of electron groups around N is \( 3 + 1=4 \), where 3 are bonding groups and 1 is a lone pair).

Step2: Determine the molecular geometry

Molecular geometry considers only the bonding atoms. For a central atom with 3 bonding groups and 1 lone pair (using the VSEPR theory, \( \text{AX}_3\text{E} \) notation where A is the central atom, X is the surrounding atom, and E is the lone pair), the molecular geometry is trigonal pyramidal. The lone pair - bonding pair repulsions cause the bonding pairs to be pushed down from the ideal tetrahedral angle, resulting in a trigonal pyramidal shape.

Answer:

trigonal pyramidal