Chemistry 10/20/11

Brainteaser Thurs. 10/20/11 Write formulas (use the crisscross method to help) for the following compounds (SOME might have polyatomic atoms): –Gallium nitride –Zinc hydroxide –Aluminum sulfide *Remember: -ide is the suffix for an anion (the negatively charged ion)*

Resources A great periodic table to use to help you remember naming is available at: s.pdf s.pdf

Cation (+) + Anion (-) = Ionic Bond Metal + Non-Metal = Ionic Bond Remember : Opposites Attract (electrostatic forces!) Ionic Bonds

Step 1: –Cation is written first in the name; anion is written second in the name Name of cation is the same as the neutral atom element (Na + = Sodium) Step 2: –Anion is written by adding the suffix –ide to the root of the element name (I - = iodide) For example: NaCl = Sodium Chloride, Al 2 O 3 = Aluminum oxide Step 3: –Transition metals- the cation’s charge is in parenthesis between the cation and anion –FeO ( Fe 2+ and O 2- ) = Iron (II) Oxide Step Four: Check your work Naming Ionic Compounds

KF AlF 3 KCl Na 3 P Fe 2 O 3 Practice Naming Ionic Compounds

Solid at room temperature Electrical conductivity –Conducts electricity when dissolved in water or in liquid (molten) form –Dissociated ions can carry charge through the solution Hardness –Hard but brittle –Electrostatic repulsion Melting points and Boiling points –High melting and boiling point –Forces of attraction between positive and negative ions are strong Demo: Properties of Ionic Bonding

Solid NaCl Liquid NaCl Electrical Conductivity

Why are crystalline solids brittle, whereas metallic solids are malleable? Structure and Properties

Brittleness Structure and Properties

Properties of Ionic Bonds Atoms are packed into a regular repeating pattern –This is a crystal! The strong attraction between the + and – charges form a crystal lattice

Properties of Ionic Bonding Crystal Lattice of Ionic Bonds

Examples of Ionic Formulas What is the formula of each of these compounds?