Ions and Ionic compounds

What is an ion?

An atom or group of atoms that has lost or gained electrons.

Cation

A positive ion formed by losing electrons.

Anion

A negative ion formed by gaining electrons.

Ionic Bond

The attraction between oppositely charged ions that forms an ionic compound.

Naming Metal Ions

Keep the element name, e.g. Magnesium ion (Mg²⁺).

Naming Non-metal Ions

Change the ending to -ide, e.g. Chloride ion (Cl⁻).

Polyatomic Ion

An ion made up of more than one atom that stays together.

Sulfate

A polyatomic ion with the formula SO₄²⁻.

Nitrate

A polyatomic ion with the formula NO₃⁻.

Ionic Compound Formation

A metal gives electrons to a non-metal, forming cations and anions that attract to create an ionic bond.

Example of Ionic Compound Formation

Sodium (Na) + Chlorine (Cl) → Sodium chloride (NaCl).

Naming Two-element Ionic Compounds

Metal name + non-metal name ending in -ide, e.g. Magnesium chloride.

What happens in a Precipitation Reaction?

Two solutions mix and form an insoluble solid (precipitate).

Example of a Precipitation Reaction

Silver nitrate + sodium chloride → silver chloride (precipitate) + sodium nitrate.