Mass spectrometry

Atoms that have the same number of protons but different numbers of neutrons are known as isotopes.

Isotopes have different atomic masses.

The relative abundance of an isotope is the percentage of atoms with a specific atomic mass found in a naturally occurring sample of an element.

The average atomic mass of an element is a weighted average calculated by multiplying the relative abundances of the element's isotopes by their atomic masses and then summing the products.

The relative abundance of each isotope can be determined using mass spectrometry.

A mass spectrometer ionizes atoms and molecules with a high-energy electron beam and then deflects the ions through a magnetic field based on their mass-to-charge ratios m/z

The mass spectrum of a sample shows the relative abundances of the ions on the y-axis and their m/z ratios on the x-axis. If z = 1 for all ions, then the x-axis can instead be expressed in units of atomic mass (u).