gcsescience.com                                                 5                                                 gcsescience.com

Atomic Structure

What are Chemical Reactions?

Why do Chemical Reactions Happen?

All chemical reactions happen because atoms are trying
to get a full outer shell of electrons.
The total number of atoms is the same before and after the reaction.

When an atom reacts with another atom to form a chemical bond
it will either
1. Lose electrons to form a stable positive ion.
2. Gain electrons to form a stable negative ion.
or  3. Share electrons to form a stable molecule.

What is the Difference between an Atom and an

An atom has the same number of protons and electrons.
An atom has no overall electric charge.

If an atom loses or gains electrons it is no longer called an atom.
It is called an ion. An ion has a full outer shell of electrons.
An ion is either positive or negative because it has an electric charge.

        Links        Revision Quizzes        Revision Questions        next

gcsescience.com    The Periodic Table    Index    Atomic Structure Quiz    gcsescience.com

Home      GCSE Chemistry      GCSE Physics

Copyright © 2015 gcsescience.com. All Rights Reserved.