When electrons are removed from the outermost shell of a calcium atom, what does the atom becomes?

The electronic configuration of $C a$ metal, $Z = 20$, is $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 4 {s}^{2}$. When the valence electrons are removed, calcium reverts to a $\left[A r\right]$ configuration. Does this address your question?