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

An electron is a subatomic particle with a negative charge and a very small relative atomic mass of 0.0005.

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.

Atomic structure (very small electron mass)

Chemistry

In the Calculations involving mass unit, pupils will learn about calculating the relative formula mass of reactants and products in balanced chemical reactions, and the conservation of atoms and mass, as well as the concept of moles (HT only).

In the Patterns in the periodic table unit, pupils learnt how the chemical and physical properties of different elements are indicated by their position on the periodic table and about key groups of elements. 

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.

This lesson will soon be taken down.

Atomic structure (very small electron mass)

Lesson outcome