Final answer:
The Lewis dot structure for calcium as an ion is Ca2+ with no dots around it, as it has lost all valence electrons. The formal charge of the calcium ion is +2.
Step-by-step explanation:
The student's question involves drawing the Lewis dot structure for the element calcium (Ca) and showing the formal charges of all atoms in the structure. For calcium, which is in group 2 of the periodic table, it typically loses its two valence electrons to form a cation with a 2+ charge. Therefore, the correct Lewis electron dot diagram for calcium after it has formed an ion would be Ca2+ with no dots around it because it has lost its valence electrons. In this state, the formal charge of the calcium ion is +2.
It is important to note that calcium as a neutral atom would be represented with two dots (its two valence electrons) before the formation of an ion. When it becomes Ca2+, however, it does not have any valence electrons left, thus no dots are shown in the Lewis dot structure of Ca2+.