Ionic Compounds and Metals- Unit 4

Chemical bond

Force that holds two atoms together

Valence electrons

Electrons involved in bonding

Ionic bond

Formed through electron transfer (results in neutral compound)

Octet

Stability found with 8 valence electrons

Cations

Formed when one or more valence electron is lost, positively charged

Anions

Formed when one or more valence electrons are gained, negatively charged ion

Formula Unit

Chemical formula for ionic compound

Swap and drop method

Method used to simplify ionic compounds, take the number on top and switch it and then bring it down

Polyatomic ions

Made up of more than one atom with overall charge. Is polyatomic if is has 3 or more element symbols, parentheses, or ends in something other than ide

Naming

Cations- same name as element, use Roman numerals for transition metals

Anions- ending changes to ide when naming (oxygen- oxide)

Peroxides

Oxygen has minus one charge, elements in groups 1 and 2 can combine to form peroxides. K2O2 is potassium peroxide. PbO2 could not be lead peroxide because lead is not in groups 1 or two.

What structure are ionic compounds in

Crystal lattice structure

What is the lattice structure

Cations and anions together in a repeating pattern

Lattice energy

Energy required to separate one mole of the ions of an ionic compound

Lattice energy rules

Smaller ions and higher charge ions produce stronger attraction and higher lattice energy (magnitude of charge is more important)

Properties of ionic compounds

High melting points, brittle and hard, generally dissolves in water, good conductors of heat and electricity when molten or dissolved in water, become electrolytes in water

What happens when ionic compounds become electrolytes

While in crystal lattice, particles are not in movement and are bad for conductivity. In water, the particles dissociate and become mobile ions that carry electrical current and can move and conduct. Strong electrolytes have extensive current flows

Electron sea model

All metal atoms in a metal solid contribute valence electrons to a sea of electrons. These electrons move freely in an electron cloud with positive ions inside.

What are the properties of metals?

Moderate to high melting points and very high boiling points due to strong electrostatic attraction requiring immense energy to separate atoms. They are malleable and ductile because ions slide by each other easily due to the sea of electrons moving freely. Shiny- electrons readily absorb and reemit photons. Conducts heat and electricity- free electrons easily move and carry charge and heat. Hard- based on number of valence electrons (more means harder),

What is a metal alloy?

A homogeneous mixture of metals defined by a metal bonding character. Properties are often superior to metals that compose them.