The Lewis structure for Ca²⁺ (calcium ion with a +2 charge) is quite simple. Calcium (Ca) is a group 2 element, which means it has 2 valence electrons in its neutral state. When calcium loses these 2 electrons to form a Ca²⁺ ion, it no longer has any valence electrons.
In the Lewis structure, we represent the nucleus and the inner electrons of the ion. Since Ca²⁺ has lost its valence electrons, the Lewis structure for Ca²⁺ is just the symbol for calcium (Ca) with a +2 charge indicated:
Ca²⁺
There are no dots around the symbol because there are no valence electrons left to represent. The +2 charge indicates that the ion has lost two electrons.