Download Unit 6: Covalent Bonds Review KEY

21.
What is the basis of the VSEPR theory?

22.
Electron pairs repel each other in a molecule. Most stability with largest bond
angles.
What happens to the bond angles as:
a. The number of lone pairs increase?

The bond angles decrease
b. The number of bonds increase?

23.
What two factors determine whether or not a molecule is polar?

24.
Bond polarity and molecular shape (lone pairs = asymmetric = more polar)
In water, two hydrogen atoms are bonded to one oxygen atom. Why isn’t water a linear
molecule?

25.
The bond angles decrease
Water is not linear because the oxygen atom has 2 lone pairs.
Label the following bonds as being nonpolar covalent, polar covalent or ionic, based on
electronegativity difference:
3.0 – 1.0 = 2.0
c. P-Br
Ionic
b. N-O
3.5 – 3.0 = 0.5
d. F-F
Polar Covalent
What is the meaning of the phrase “Like Dissolves Like.”
a. Ca-Cl
26.

2.8 – 2.1 = 0.7
Polar Covalent
4.0 – 4.0 = 0
Nonpolar Covalent
Compounds will dissolve if the solvent has the same polarity. Polar dissolves
polar, but not nonpolar.
Predict the molecular geometry and indicate the polarity for the compounds in the table.
Formula
Lewis Structure
Shape
Molecule Polarity
27.
SiO2
Linear
Nonpolar
28.
NF3
Trigonal
Pyramidal
Polar