Atomic number of which of the following elements is greater than that of Calcium?

The atomic number of Calcium ($\text{Ca}$) is $20$. Let's look at the atomic numbers of the given options:Chlorine ($\text{Cl}$) = $17$ Argon ($\text{Ar}$) = $18$ Sulphur ($\text{S}$) = $16$ Scandium ($\text{Sc}$) = $21$ Since $21>20$, Scandium has a greater atomic number than Calcium.