Atoms, Elements and Compounds

An element is made up of one type of atom

A compound is made up of two or more elements

An atom is a tiny particle that makes up all substances

An ion is a charged particle formed when an atom, or a group of atoms, loses or gains electrons

A mixture consists of two or more different substances that are not chemically joined together

Plum Pudding Model - JJ Thomson, atom ball of positive charge with negative electrons in it 

Nuclear Model - Rutherford, 1909, mass of atom concentrated in the centre, called the nucleus, nucleus positively charged - Bohr showed electrons orbiting nucleus in shells and protons included in nucleus

Modern Atomic Model - Chadwick discovered neutrons in 1932 and the model became what we use today