Isotopes are atoms of the same element with different number of neutrons and the same number of protons. React chemically the same but have a different masses
Ions are atoms or groups of atoms that have either lost or gained electrons so they have a positive or negative charge.
The Actinides also known as the actinoids are a set of elements in the final period of the periodic table from elements 89 to 103. They are a series of radioactive elements with similar properties.
By the 1930’s the atom consisted of a proton as a positive area of charge and electrons orbiting it but there was still a piece missing. It was not until 1932 that James Chadwick discovered a particle with the same mass of a proton but no overall charge, the neutron.