GCSE AQA Chemistry Notes

Atoms

All substances are made of atoms. There are about 100 different types of atoms found naturally on Earth. The elements in the periodic table are arranged in columns, called groups. Each group contains elements with similar chemical properties. 

Compounds are made up of different types of atoms joined together. Chemmical bonds holds the atom tighly together in compounds. 

An atom is made up of a tiny central nucleus with electrons around it. 

In the nucleus, which is in the middle of the atom there are protons and neutrons. Electrons are found in the shells, which surround the nucleus. 

Any atom has the same number of electrons orbiting its nucleus as iit has protons in its nucleus. 

Protons has positvie charges. Neutrons have no charge, and are therefore neutral. This means that the…