Name__________________________________________ Per _______ Date _______________________
6.5 Practice Worksheet A
Determining Molecular Geometry & Polarity using VSEPR Theory
Knowing the ______________________ and __________________ of a molecule, can help scientists to predict its physical and
__________________ behavior.
Directions: Write a Lewis structure for each of the following. Then using VSEPR theory, determine if the molecule is polar or nonpolar.
Formula
Cl2
CH4
NH3
H2O
BF3
HCN
Lewis Structure
Type of
Molecule
Geometry
Revised Lewis Structure
Overall Polarity
Intermolecular Forces
How do we predict the geometry and polarity of a molecule using VSEPR theory?
1. Draw a Lewis structure for the molecule.
VSEPR theory states: if any lone pairs of electrons are found on the __________ atom, these electrons decrease the bond angles of
atoms attached to it. What are lone pairs?
2. Draw a revised Lewis structure to show a more accurate picture of how lone pairs (or a lack of lone pairs) have affected the shape of the
molecule.
3. To indicate the polarity of the bonds, we use this symbol: __________________ , which always points toward the more electronegative
element.
Electronegativity
4. When multiple bonds are found in a molecule, we must identify polarity of ________ bond.
5. Observe the overall polarity of the molecule. Think of it as “tug-of-war” for valence electrons between the various atoms.
- ______________ molecules: If the atom is symmetrical and all atoms have an equal pull on electrons
- ___________________ molecules: If the atom is not symmetrical and/or the atoms do not all have an equal chance of winning
the tug of war for electrons
Summary of Bond Polarity:
- Bent and trigonal pyramidal molecules are always _______________________ .
- Linear, trigonal planar, and tetrahedral are often ____________________, but can be ____________________, if all the atoms
attached to the center are not the same.