Answer:
Ca2-, Ca, and Ca2+
Step-by-step explanation:
Alright, let's unravel the radius hierarchy:
1. Ca2-: An ion with a negative charge means it has gained electrons, causing it to be larger than its neutral counterpart.
2. Ca: This is the neutral state, and it's smaller than the Ca2- ion. When calcium loses electrons to form an ion, it becomes more compact.
3. Ca2+: Similar to the Ca2- ion, but in this case, calcium has lost electrons. The loss of electrons results in a smaller electron cloud, making it smaller than the neutral calcium atom.
Ca2-, Ca, and Ca2+