A metal M forms $\text{M}^{2+}$ ions. The charge passed and the mass of M deposited were measured. Charge in C: $1930$, $3860$, $5790$. Mass in g: $0.587$, $1.174$, $1.761$. Which metal is M? Molar masses in g/mol: Mg $24.3$, Ni $58.7$, Cd $112.4$, Hg $200.6$.