A molecule is a particle consisting of a fixed number of (two or more) non-metal atoms covalently bonded together.

When an atom has a full outer shell of electrons, it has a noble gas electron configuration.

The outer shell is the highest energy level in an atom and is usually the furthest from the nucleus.

Why chemical reactions happen

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

The arrangement of electrons in shells, in an atom or ion.

The highest energy level in an atom, contains electrons.

Match the following terms to the correct definitions.

In which of the following are electrons donated and accepted?

Which of the following are monoatomic substances?

What type of bonding forms between non-metal atoms?

It does not have a full outer shell of electrons.

The outer shell contains eight electrons.

Why is an oxygen atom considered to be unstable?

Which of the following diagrams shows an ionic substance?

Relative mass of an atom, the total mass of its protons and neutrons.

Number of protons in the nucleus of an atom of an element.

The smallest particle of an element that can exist.

A group of atoms chemically bonded together.

Match the following terms to the correct definition.

Oxygen has an atomic mass of 16 and an atomic number of 8. How many electrons does an atom of oxygen have?

Lithium is in Group 1, period 2 of the periodic table. It has an atomic number of 3. How many electrons are found in the outer shell of a lithium atom?

Which of the following are examples of diatomic molecules?

Protons and electrons are found in the nucleus of atoms.

Which of the following statements about subatomic particles are correct?

Starter Quiz