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Mathematics for Physics

63 Ionization

A process of removing an electron from an atom that is used to create a positively charged ion from a previously neutral atom, where an ion is an atom that carries a net charge.

Single ionization. Removing one electron of charge \(-e\) from a neutral atom leaves a positive ion of charge \(+e\). The elementary charge is the magnitude of the charge of the electron. This principle is used to assign the charge of a singly ionized atom.

The charge after one-electron ionization is

\[ q = +e \]

where

  • \(q\) is the charge of the positive ion.
  • \(e\) is the elementary charge.

Multiple ionization. Removing \(n\) electrons from a neutral atom yields charge \(+ne\). This principle is used to describe multiply ionized atoms.

The charge after removing \(n\) electrons is

\[ q = +ne \]

where

  • \(q\) is the charge of the ion.
  • \(n\) is the number of electrons removed.
  • \(e\) is the elementary charge.

Charge balance of the freed electron. The removed electron carries charge \(-e\) and is free of the atom. This principle is used to count both the ion and the free electron in a charge balance.