What is the formula when the halogen from 3rd principal energy level combines with you alkaline earth metal from the 4th energy level?

Explanation:

Principle Quantum Numbers : It describes the size of the orbital and the energy level. It is represented by n. Where, n = 1,2,3,4....

Halogen with n=3 is chlorine.

Alkaline earth metal with n = 4 is calcium.

An ionic bond is formed when an element completely transfers its valence electron to another element.

Electronic configuration of calcium

calcium atom will loose one electron to gain noble gas configuration and form calcium cation with +2 charge.

Electronic configuration of chlorine:

Chlorine atom will gain one electron to gain noble gas configuration and form chloride ion with -1 charge.

Here cation and chloride anion combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .

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