Final answer:
Calcium (Ca) and sulfur (S) in CaS form an ionic bond, with calcium becoming a Ca2+ cation and sulfur becoming an S2- anion, creating the ionic compound calcium sulfide (CaS).
Step-by-step explanation:
The elements calcium (Ca) and sulfur (S) bond to form an ionic bond in the compound calcium sulfide (CaS). Calcium is a metal from group 2 and tends to form cations (positively charged ions) by losing two electrons and becoming Ca2+. Sulfur is a nonmetal from group 16 and tends to form anions (negatively charged ions) by gaining two electrons and becoming S2-. The transfer of electrons from calcium to sulfur results in the formation of an ionic compound due to the electrostatic attraction between oppositely charged ions.
Each substance's classification:
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- Calcium (Ca) when neutral is an atomic element.
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- Sulfur (S) when neutral is an atomic element.
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- When bonded in CaS, they form an ionic compound.
Therefore, in CaS, a calcium atom is transformed into a cation and a sulfur atom into an anion as a result of electron transfer.