Chapter 8 Test Review

Polar- unequal sharing of electrons Non-polar - equal sharing of electrons Electronegativity- ability to attract electrons

Ionic CompoundsMolecular Compounds Crystal LatticeMolecule Types of Elements Metal with non-metal or polyatomic ions Non-metal with non-metal Physical State SolidSolid, liquid or gas Melting PointHigh > 300  C Low <300  C Solubility in water Generally highGenerally low Electrical conductivity of solution Good conductorPoor 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? CH 3 OH CH 4 PF 3 OF 2 NO 2 - BH 3 SO 4 2- CN - N 2 H 2

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 SiS 4 PCl 5 CCl 4 NO

Writing Formulas Sulfur difluoride Silicon tetrachloride Chlorine trifluoride Tetrasulfur heptanitride

Lewis structures CH 3 OH BH 3 N 2 H 2

Lewis Structures with polyatomic ions SO 4 2- CN -

Molecular Shapes CH 4 PF 3 OF 2 NO 2 -

Lewis Structures with resonance NO 3 – CO 3 2-