Table for Answering Lewis Structures and VSEPR Theory Practice Questions
Molecule and Identity Calculation of the number of
Final Lewis Structure (Get another
of the central atom
valence electrons in the Lewis
piece of paper and FOLLOW THE
Structure
STEPS IN YOUR NOTES!!! to get
this.)
Carbon tetrachloride,
CCl4
Central atom is C
1 C 1 atom x 4 val electrons = 4e14 Cl 4 atoms x 7 val electrons = 28 e1Total = 32e1-
Cl
Cl
C
Cl
Cl
There is a total of 32 electrons in this Lewis
structure. This is not a polyatomic ion so it
does not need square brackets and a charge. It
is not a resonance structure so only one
structure needs to be shown.
Predicted VSEPR formula
and VSEPR shape
(remember to count
multiple bonds as one bond
when figuring out the
VSEPR formula)
I know the VSEPR Formula is
AX4 so the molecular shape
is tetrahedral.
Recall:
A = central atom
X = number of atoms
attached to central atom
E = number of lone pairs on
the central atom
3-D Diagram of the VSEPR shape
(include bond dipoles, bond angles and
partial charges)
Bond angles are all 109.5o in a tetrahedron.
Bond dipoles all go from C to Cl with C
slightly positive (δ+) and all Cl atoms slightly
negative (δ-) because Cl has the higher
electronegativity value.
Is the Molecule Polar or is it Nonpolar? (include an explanation for
your answer.)
This molecule contains polar
covalent bonds but it is a non-polar
molecule because there are no lone
pairs on the central atom and the
molecule is symmetrical about the
central atom so all of the bond
dipoles will cancel one another out.