Solution By Steps

Step 1: Determine the Lewis Structure

To find the molecular geometry, start by drawing the Lewis structure of PF3.

Step 2: Count Valence Electrons

Phosphorus contributes 5 valence electrons, and each fluorine contributes 7 valence electrons. Total valence electrons = 5 § + 3(7) (F) = 26.

Step 3: Connect Atoms with Single Bonds

Connect phosphorus § with three fluorine (F) atoms using single bonds.

Step 4: Distribute Remaining Electrons

Place the remaining electrons around the fluorine atoms to satisfy the octet rule. Phosphorus may have more than 8 electrons.

Step 5: Determine Molecular Geometry

PF3 has a trigonal pyramidal molecular geometry. The lone pair on phosphorus causes this shape.

Final Answer

The molecular geometry of the PF3 molecule is trigonal pyramidal, and this molecule is polar.

Key Concept

Molecular Geometry

Key Concept Explanation

Molecular geometry describes the arrangement of atoms in a molecule. It influences the molecule’s properties, such as polarity and reactivity.