Atomic structure - Topic 1.2 - Definitions

Isotopes

Isotopes

Atoms which have the same atomic number but different mass numbers

Relative isotopic mass (RIM)

The mass of an atom of an isotope of an element relative to one-twelfth of the mass of an atom of carbon-12

Relative atomic mass (RAM)

The average (weighted mean) mass of an atom of an element relative to one-twelfth of the mass of an atom of carbon-12

Relative formula mass (RFM)

The average (weighted mean) mass of a formula unit relative to one-twelfth of the mass of an atom of carbon-12

Relative Molecular Mass (RMM))

The average (weighted mean) mass of a molecule relative to one-twelfth of the mass of an atom of carbon-12

Applies to cov

Mass spectrometer

A machine that allows us to work out RAMs and isotopic abundances for elements

Orbital

A region in an atom that can hold up to two electrons with opposite spin

Principal quantum numbers

K, L, M, N (etc)