Warm Up For the following molecules, Draw the Lewis Dot Structures, Predict the shape, Tell if the bonds are polar or nonpolar, and tell if the molecule itself is polar or nonpolar: H2S O2 CCl4

Warm-up Predict the shape and polarity of the following covalent molecules OF2 H2 CH4 PCl3

Properties of Bonds Bonding, Day Five

Strength of Bonds Non-polar bonds are the weakest Then come polar And the strongest bonds are ionic Bond strength is measured by boiling points and melting points the stronger the bond, the higher the melting point and boiling point.

Properties of Ionic Compounds Ionic bonds are the strongest!! Composed of positive and negative ions Form between a metal and a non-metal or a metal and a polyatomic ion Solids at room temperature When bonded, they are arranged very neatly – become crystals High melting points and boiling points Brittle Conduct electricity when dissolved in water

Properties of Covalent Compounds Smallest unit is a molecule May be solid, liquid, or gas Low melting and boiling points Covalent solids are softer than ionic solids Do not conduct electricity

Comparing within Covalent Polar Covalent Non-Polar Covalent Dissolve in water Stronger bonds (but not as strong as ionic) Higher melting and boiling points Exist as solids or liquids at room temperature Ex: H2O, sugar Do not dissolve in water Very weak bonds Low melting points and low boiling points Exist as gases at room temperature Ex: O2, H2

Properties of Metallic Compounds Shiny Malleable Ductile Crystalline Solid at room temperature (except for Hg) Melting points vary widely Good conductors of heat and electricity Do not dissolve in water

Type of Molecule Dissolve in Water? Conduct Electricity? Metallic No Yes Ionic Polar Covalent Non-Polar Covalent

Na2S CBr4 SO3 CaI2 PCl3 N2