Calcium is an element well-known for its role in building strong bones and teeth, but chemically, it has a fascinating behavior when forming ions. The most common ion charge for calcium can be found in the following options:
A. +1
B. +2
C. -1
D. -2
The correct answer is B. +2.
Calcium, with an atomic number of 20, has 20 electrons arranged as 2, 8, 8, 2. To achieve a stable electron configuration like argon, calcium loses its two valence electrons, forming a Ca2+\text{Ca}^{2+} ion. This makes the most common ion charge for calcium +2.
