Atomic structure

• An isotope is an atom of the same element, with the same number of protons and electrons but a different number of neutrons.
• Relative atomic mass is the weighted mean mass of an atom of an element compared to 1/12th the mass of an atom of carbon-12.
• Relative isotopic mass is the mass of isotope of an element compared with 1/12th of the mass of a carbon-12 atom.