Write the chemical formula of the following compounds: Calcium Sulfide
The correct answer and explanation is:
The chemical formula for calcium sulfide is CaS.
Explanation:
To determine the chemical formula of calcium sulfide, it’s essential to understand the charges of the ions involved.
- Calcium Ion (Ca²⁺): Calcium, being an alkaline earth metal, has two valence electrons, which it readily loses to form a stable cation with a charge of +2. Therefore, the calcium ion is written as Ca²⁺.
- Sulfide Ion (S²⁻): Sulfur, located in group 16 of the periodic table, has six valence electrons and requires two additional electrons to achieve a full outer shell, which results in the formation of an anion with a charge of -2. This ion is written as S²⁻.
- Combining the Ions: When calcium and sulfur combine to form calcium sulfide, the total positive charge from the calcium ion must balance the total negative charge from the sulfide ion. Since calcium has a +2 charge and sulfide has a -2 charge, the ratio of calcium ions to sulfide ions is 1:1.
- The Formula: With a one-to-one ratio of calcium ions to sulfide ions, the formula of calcium sulfide is CaS.
This process of balancing the charges ensures the compound is neutral. Calcium sulfide is an ionic compound, meaning it is formed by the electrostatic attraction between oppositely charged ions.
This compound is typically found as a white solid and is often used in the production of phosphors, in chemical syntheses, and in some specialized applications.