Answer:
[tex]CaS[/tex]
Explanation:
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In this case, since calcium's oxidation state when forming ionic bonds is +2 and sulfur's oxidation state when bonding those bonds is -2, for the required formula we write:
[tex]Ca^{2+}S^{2-}[/tex]
Now, since they have the same charge number, we infer the ionic compound formed when they bond is calcium sulfide:
[tex]CaS[/tex]
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