what is an ion?
an ion is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons

how are they formed?

• Ions are electrically charged particles formed when atoms lose or gain electrons. They have the same electronic structures as noble gases. Metal atoms form positive ions, while non-metal atoms form negative ions. The strong electrostatic forces of attraction between oppositely charged ions are called ionic bonds. Ionic compounds have high melting and boiling points.

how do you write the chemical formula?

• When writing the formula for the ionic compound, the cation comes first, followed by the anion, both with numeric subscripts to indicate the number of atoms of each. Polyatomic ions are a set of covalently bonded atoms that have an overall charge, making them an ion.

Untitled Slide