1. C1a Patterns in Properties
Lesson 2 Pupil Information Sheet – Atomic Structures
Key
1
Mass number A →
H
Hydrogen
Atomic number (also called Proton number) Z → 1
There is a nucleus at the centre of each atom that contains most of its mass.
The nucleus contains two types of particle: protons and neutrons. Protons are positively charged.
Neutrons have no charge (are neutral).
Clouds of smaller particles called electrons surround the nucleus. Electrons are negatively charged
and are arranged in shells. Each electron shell has a maximum number of electrons that it can hold:
Electron shell Maximum
number of
electrons
1 2
2 8
3 8
4 18
Every atom contains an equal number of protons and electrons. This means that an atom also has an
equal number of positive and negative charges, so it is neutral overall.
Follow the example below, for aluminium, before then drawing the atomic structures of the elements
on your pupil worksheet:
27
Al
Aluminium
Atomic number (also called Proton number) Z → 13
Therefore, number of protons in the nucleus = 13
number of electrons = 13
Aluminium atom

2. Name:
C1a Patterns in Properties
Lesson 2 Pupil Worksheet – Atomic Structures
For each element shown below, find the atomic number on the periodic table and use it to draw the
atomic structure of its atom.
magnesium chlorine
hydrogen helium
carbon
oxygen neon
sulphur