An atom or molecule that has lost or gained one or more electrons so has a charge.

Used to show how chemical bonds are formed between atoms – the electrons from one atom are shown as dots and the electrons from the other atom are shown as crosses.

Forming ions for ionic bonding

Combined science

In the Chemistry of Carbon unit, pupils will build on their understanding of chemical bonding to explore the unique properties and bonding of carbon, leading to various natural and synthetic organic compounds.

In the Atomic Structure and the Periodic Table unit, pupils learned about the model of the atom, isotopes, and the arrangement of elements in the periodic table.

Structure and bonding

An atom or molecule that has gained or lost electrons so has a charge.

Match the following terms to their definitions.

Atoms become more {{}} when they have a full outer shell of electrons.

When a magnesium atom forms an ion, it loses two electrons. What charge does a magnesium ion have?

Boron (B) is in Group 3 of the periodic table. Which of the following correctly represents a boron ion?

Non–metal atoms lose electrons to become more stable.

Metal atoms lose electrons to become more stable.

An oxygen atom is reperesented by the symbol O²⁻.

A calcium ion is represented by the symbol Ca²⁺.

Which of the following statements are correct?

It gains an electron to form a negative ion.

It loses an electron to form a negative ion. 

It gains an electron to form a positive ion.

It loses an electron to form a positive ion.

Chlorine is in Group 7 of the periodic table. What happens to a chlorine atom in order for it to form a stable chloride ion?

Which of the following subatomic particles are found in the nucleus of an atom?

Match the following subatomic particles to the correct charge.

They contain the same number of protons as electrons.

They contain the same number of protons as neutrons.

They contain the same number of neutrons as electrons.

Oxygen is in Group 6 of the periodic table. How many electrons does an oxygen atom have in its outer shell?

A potassium atom has 19 electrons in total. How many electrons are there in the outer shell of a potassium atom?

A sulfur atom has six electrons in its outer shell.

A sulfur atom has three electrons in its outer shell.

A sulfur atom has three shells of electrons.

A sulfur atom has six shells of electrons.

Sulfur is in Group 6, Period 3 on the periodic table. What does this tell you about sulfur?

Starter Quiz