Answer
$Argon$
Work Step by Step
The atomic numbers $(Z)$ of the existing noble gases are $2,10,18,36,54,86,118$.
Suppose that the electron had no spin and that the Pauli exclusion principle still held. In this condition the the atomic numbers $(Z)$ of the noble gases will be $1,5,9,18,27,43,59$
In both cases, $18$ is common atomic number. Therefore, the noble gas $Argon$ (Z=18) will remain in this category.
