atoms

proton number - number of protons in the nucleus of an atom Bigger number - smaller number

nucleon number - number of protons and neutrons in the nucleus

relative atomic mass, g/mol O2 Ar = 16 g/mol

relative formular/molecular mass eg MgO = 24.3 + 16 = 40.3 g/mol

carbon-12 is the standard unit of measurement for the relative masses

carbon amu = 12 1 amu = 1/12 of carbon

weighted mean mass of an atom of an element compared to 1/12 of the mass of an atom of carbon-12

mass of 1 atom of an isotope relative to 1/12 of the mass of 1 atom of carbon-12

Relative molecular mass of a compound is the mass of a molecule of the compound relative to 1/12 of the mass of one atom of Carbon-12

Technique used to determine the composition of a substance e.g. isotopes Can be used to determine the structure of organic molecules

Mass in grams of 1 mole of a substance, g mol-1

Volume of 1 mole of a gas at a given temperature and pressure All gases have this same volume At room pressure (1 atm) and room temperature (25C), the molar gas volume is 24dm3 mol-1

1 mole contains NA 6.02x10^23 atoms/molecules/ions

Simplest ratio of atoms of each element in the compound

Actual number of atoms of each element in the compound

(Abundance 1/100 x RIM) + (abundance 2/100 x RIM 2)

Different neutrons 79Br has 44 neutrons, 81Br has 46 neutrons

Losing 2 electrons, OILRIG