Atomic Structure

• The three subatomic particles that make up an atom are protons, neutrons, and electrons.
• The protons and neutrons are located inside the nucleus of the atom, and the electrons are orbiting around the nucleus in shells.
• The atomic number is the number of protons in the nucleus of the atom
• The mass number is the total number of protons and neutrons in the nucleus of the atom
• The relative mass of protons and neutrons is 1, and the relative mass of an electron is 1/1840
• The charge of a proton is +1, the charge of an electron is -1, the charge of a neutron is 0
• J.J. Thomson discovered the electron and made the Plum Pudding Model, with the "sponge" containing positive charge and the "fruits in the plum pudding" being the negatively charged electrons. This model was proved wrong by Ernst Rutherford, who proved that the atom consisted of electrons revolving around the positively charged nucleus.
• James Chadwick discovered the neutron in 1932.
• R.A.M. (Relative atomic mass) is worked out by:

  (M1 × Abundance 1) + (M2 × Abundance 2)/ Abundance 1 + Abundance 2
• Isotopes are atoms of the same element with the same number of protons, but different numbers of neutrons
• An ion is an atom that has lost or gained 1 or more electron, and thus has a charge
• Hydrogen and the metal elements lose electrons and become positive ions(cations)
• Non metal elements gain electrons and become negative ions(anions)
• The charge of a non ion atom is always 0