The Isotopes command returns the isotopes of a given element.

The output is a list of the isotopes specified by an atomic symbol and subscript.

The subscript indicates the total number of protons and neutrons in an atom of the isotope.  

Two isotopes of an element have the same number of electrons and protons but different numbers of neutrons.

$\mathrm{with}\left(\mathrm{QuantumChemistry}\right)\:$

$\mathrm{Isotopes}\left(''Na''\right)\;$

$\left[{\mathrm{Na}}_{18}\,{\mathrm{Na}}_{19}\,{\mathrm{Na}}_{20}\,{\mathrm{Na}}_{21}\,{\mathrm{Na}}_{22}\,{\mathrm{Na}}_{23}\,{\mathrm{Na}}_{24}\,{\mathrm{Na}}_{25}\,{\mathrm{Na}}_{26}\,{\mathrm{Na}}_{27}\,{\mathrm{Na}}_{28}\,{\mathrm{Na}}_{29}\,{\mathrm{Na}}_{30}\,{\mathrm{Na}}_{31}\,{\mathrm{Na}}_{32}\,{\mathrm{Na}}_{33}\,{\mathrm{Na}}_{34}\,{\mathrm{Na}}_{35}\right]$

$\mathrm{Isotopes}\left(\mathrm{Na}\right)\;$

$\left[{\mathrm{Na}}_{18}\,{\mathrm{Na}}_{19}\,{\mathrm{Na}}_{20}\,{\mathrm{Na}}_{21}\,{\mathrm{Na}}_{22}\,{\mathrm{Na}}_{23}\,{\mathrm{Na}}_{24}\,{\mathrm{Na}}_{25}\,{\mathrm{Na}}_{26}\,{\mathrm{Na}}_{27}\,{\mathrm{Na}}_{28}\,{\mathrm{Na}}_{29}\,{\mathrm{Na}}_{30}\,{\mathrm{Na}}_{31}\,{\mathrm{Na}}_{32}\,{\mathrm{Na}}_{33}\,{\mathrm{Na}}_{34}\,{\mathrm{Na}}_{35}\right]$

$$\begin{gathered} \mathrm{Isotopes}\left(\mathrm{sodium}\right)\; \\ \mathit{ } \end{gathered}$$

$\left[{\mathrm{Na}}_{18}\,{\mathrm{Na}}_{19}\,{\mathrm{Na}}_{20}\,{\mathrm{Na}}_{21}\,{\mathrm{Na}}_{22}\,{\mathrm{Na}}_{23}\,{\mathrm{Na}}_{24}\,{\mathrm{Na}}_{25}\,{\mathrm{Na}}_{26}\,{\mathrm{Na}}_{27}\,{\mathrm{Na}}_{28}\,{\mathrm{Na}}_{29}\,{\mathrm{Na}}_{30}\,{\mathrm{Na}}_{31}\,{\mathrm{Na}}_{32}\,{\mathrm{Na}}_{33}\,{\mathrm{Na}}_{34}\,{\mathrm{Na}}_{35}\right]$