Answer
$\because\;\;\lambda_{avg}\lt\lt d_{avg}$, the atoms can be treated as particles under these conditions.
Work Step by Step
The average de Broglie wavelength of helium gas is given by
$\lambda_{avg}=7.30\times 10^{-11}\;m=0.073\;nm$
The average distance between atoms is given by
$d_{avg}=3.45\;nm$
$\because\;\;\lambda_{avg}\lt\lt d_{avg}$, the atoms can be treated as particles under these conditions.
