Question

part d
calcium and iodine
express your answer as a chemical formula.
a chemical reaction does not occur for this question

Explanation:

Step1: Determine the charges of calcium and iodine ions

Calcium (\(Ca\)) is in group 2 of the periodic table. So, it loses 2 electrons to form \(Ca^{2 +}\) ion. Iodine (\(I\)) is in group 17. It gains 1 electron to form \(I^{-}\) ion.

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

For a compound, the sum of the positive and negative charges must be zero. Let the formula be \(Ca_xI_y\). Using the charge balance: \((+ 2)x+(-1)y = 0\). By criss - cross (swap the magnitudes of charges), \(x = 1\) and \(y = 2\).

Answer:

\(CaI_2\)