Question

calcium and sulfur
express your answer as a chemical formula.

Explanation:

Step1: Determine the charges of calcium and sulfur ions

Calcium (\(Ca\)) is in Group 2 of the periodic table. It loses 2 electrons to form \(Ca^{2 +}\) ion. Sulfur (\(S\)) is in Group 16. It gains 2 electrons to form \(S^{2 -}\) ion.

Step2: Use the criss - cross method to write the formula

For ionic compounds, the formula is written by balancing the charges. The charge of \(Ca^{2+}\) is \(+ 2\) and the charge of \(S^{2 -}\) is \(-2\). Using the criss - cross method (the magnitude of the charge of one ion becomes the subscript of the other ion), since \(\vert+2\vert=\vert - 2\vert = 2\), the subscripts are \(1\) (when the ratio of charges simplifies to \(1:1\)).

Answer:

\(CaS\)