The HasProperty( descriptor ) command returns true if descriptor is the name of an element or isotope property in the ScientificConstants package. Otherwise, it returns false.

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

$\mathrm{HasProperty}\left(\mathrm{atomicweight}\right)$

$\mathrm{true}$

$\mathrm{HasProperty}\left(\mathrm{atomicmass}\right)$

$\mathrm{true}$