Answer:
The correct answer to the question,'when a calcium atom form an ion, it loses two electrons. What is the electrical charge of the calcium ion, is +2, that is, option D.
Step-by-step explanation:
The atomic number of calcium is 20. During chemical reactions, calcium usually donate its two electrovalent electrons to other elements, mostly non-metals, in order to become an ion with 18 electrons. Loosing two electrons make it to become electro positive with a charge of +2. The charge is +2 because it donates two electrons, the element that accept the electrons will have a negative charge because it is an acceptor. Calcium ion has postive charge because it is an electron donor.