An ion of calcium has a +2 charge, and an ion of chlorine has a –1 charge. how many chlorine ions are needed to create a stable ionic compound with an ion of calcium?

Explanation:

An ionic compound is the compound formed due to transfer of electrons from one atom to another.

Atomic number of calcium is 20 with electronic distribution 2, 8, 8, 2. So, on losing 2 valence electrons it forms ion.

Atomic number of chlorine is 17 with electronic configuration 2, 8, 7. So, on gaining one electron it forms .

As, a calcium ion has +2 charge and a chlorine ion has -1 charge.

Therefore, when both of them chemically combine together then two chlorine ions are  needed to combine with one calcium atom.

As a result, is formed.

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explanation: