Lesson 1.1 - Atoms

In this lesson:

• Atoms

• Subatomic particles

• Making elements

• Nucleus

• Electron shells

Atoms

An atom is “the smallest part of an element that can exist”.

It is the basis for elements and compounds, that it - everything is made up of atoms.

They contain three subatomic particles.

Subatomic particles

Atoms contain 3 things:

• Protons

• Neutrons

• Electrons

These three things are called subatomic particles - they are the building block of atoms.

Making elements

An element is a type of atom.

The element is determined by the number of protons in an atom.

Nucleus

Atoms contain a dense core - this is called the nucleus.

The nucleus contains the protons and neutrons.

Electron shells

The electrons orbit around the nucleus in their own energy levels.

We call these 'shells'.

The number of shells depends on the number of electrons the atom contains.

Contents

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