An electron is a subatomic particle with a negative charge and a very small relative mass of 1/1835 (negligible).

A proton is a subatomic particle with a positive charge and a relative atomic mass of 1.

A neutron is a subatomic particle with no charge and a relative atomic mass of 1.

A nucleus is found in the centre of an atom. It consists of protons and neutrons. It is significantly smaller in size than the atom.

Anything that is smaller than an atom. There are three subatomic particles called electrons, protons and neutrons.

Atomic structure (negligible electron mass)

Combined science

Developing a model for atoms

Atoms, elements and compounds

Modern periodic table and electron configuration

Atomic number and mass number

Isotopes and relative atomic mass

Relative formula mass

Development of the periodic table

In the Structure and Bonding unit, pupils will build on their understanding of atomic structure to explore different types of chemical bonding and how these bonds affect the properties of substances.

In the Atoms, Elements and Compounds unit, pupils learned about the differences between atoms, elements, and compounds, as well as their chemical symbols and formulae.

This unit covers the atomic model, relative atomic mass, isotopes, and the structure of the modern periodic table. It explains how atomic structure influences element positioning, properties, and reactivity. The focus is on identifying trends and using models to develop scientific explanations.

Atomic structure and the periodic table

Match the subatomic particles with their relative charges:

The relative mass of a neutron is {{}} (compared to protons).

they have the same numbers of protons and neutrons

they have the same numbers of protons and electrons

they have the same numbers of electrons and neutrons

True or false? Atoms are overall neutral. (Select true or false and a justification.)

Which of the following are correct ways of describing the relative mass of electrons (compared to protons)?

The radius of an atom's {{}} is at least 10 000 times smaller in comparison to the radius of the whole atom.

They are composed of multiple types of atoms.

They can be broken down into simpler substances by chemical means.

They are the simplest form of matter that can exist under normal conditions.

What determines the identity of an element?

An element is a substance made up of only one kind of ...

John Dalton's theory proposed that {{}} are indivisible.

The {{}} is a list of all known elements, ordered based on their properties.

Exit Quiz

Where is the nucleus located in an atom?