Chapter 8 Test Review
• Polar- unequal sharing of electrons
• Non-polar - equal sharing of electrons
• Electronegativity- ability to attract electrons
Ionic Compounds
Molecular
Compounds
Crystal Lattice
Molecule
Metal with non-metal Non-metal with
or polyatomic ions
non-metal
Solid
Solid, liquid or gas
Types of
Elements
Physical
State
Melting Point High
> 300 C
Solubility in Generally high
water
Electrical
Good conductor
conductivity
of solution
Low
<300 C
Generally low
Poor to none
Properties of Covalent bonds
• Bond length decreases as number of covalent
bonds increases.
• Bond strength increases as number of covalent
bonds increases
• Bond length increases as number of covalent
bonds decreases
• Bond strength decreases as number of covalent
bonds decreases.
Sigma and Pi bonds
• Sigma– Single covalent bond
• Single bond- 1 sigma
• Pi
– Multiple covalent bonds
• Double bond- 1 sigma, 1 pi bond
• Triple bond- 1 sigma, 2 pi bonds
28. Which diagram correctly depicts the trend in
electronegativity?
How many atoms in each formula?
• CH3OH
• CH4
• PF3
• OF2
• NO2• BH3
• SO4 2• CN• N2H2
Covalent Bonds
• How many covalent bonds can elements in the
following groups form:
–
–
–
–
–
–
–
–
Group 1 (alkali metals)
Group 2 (alkali earth metals)
Group 3
Group 4
Group 5
Group 6
Group 7 (halogens)
Group 8 ( noble gases)
Polar or non-polar
• Shares equally
• Does not share equally
Diatomic Molecules
• List the 7 diatomic molecules:
Naming Molecules
• SiS4
• PCl5
• CCl4
• NO
Writing Formulas
• Sulfur difluoride
• Silicon tetrachloride
• Chlorine trifluoride
• Tetrasulfur heptanitride
Lewis structures
• CH3OH
• BH3
• N2H2
Lewis Structures with polyatomic ions
• SO4 2-
• CN-
Molecular Shapes
• CH4
• PF3
• OF2
• NO2-
Lewis Structures with resonance
• NO3–
• CO32-