F321: Atoms and Reactions Definitions

Module 1: Atoms and Reactions 

Isotopes: Atoms of the same element with a different number of neutrons 

Atomic Number: The number of protons in the nucleus of an atom

Mass Number: The number of particles (protons and neutrons) in the nucleus 

An Ion: A positively or negatively charged atom or group of atoms 

Relative Isotopic Mass: The mass of an isotope compared to 1/12 the mass of an atom of carbon-12 

Relative Atomic Mass: Ar is the weighted mean mass of an atom of an elements compared with 1/12 the mass of an atom of carbon-12

Relative Molecular Mass: The weighted mean mass of a molecule compared with 1/12 the mass of an atom of carbon-12 

Relative Formula Mass: The weighted mean mass of a formula unit compared to 1/12 the mass of an atom of carbon-12

The Avogadro Constant: The number of atoms per mole of carbon-12 isotope (6.02 x 10^23 mol-1) 

A Mole: The amount of any substance containing as many particles as there as carbon atoms in…