Question

Jane answered a question on her Chemistry Quiz about bonding magnesium (Mg) and chlorine (Cl). She said the correct formula for the compound would be MgCl. Her teacher marked the answer incorrect. What could Jane do to correct her mistake?

a. She could add an atom of magnesium for a total of 2 magnesium atoms and 1 chlorine atom.
b. She could add an atom of chlorine for a total of 2 chlorine atoms and 1 magnesium atom.
c. She could add 2 magnesium atoms for a total of 3 magnesium atoms and 1 chlorine atom.
d. She could add 2 chlorine atoms for a total of 1 magnesium atom and 3 chlorine atoms.

Answer 1

Jane should correct her answer to MgCl2 by adding one chlorine atom so that there are 2 chloride ions to 1 magnesium ion, forming a stable ionic compound with a 1:2 ratio.

Step-by-step explanation:

To correct her mistake, Jane should choose option b. She could add an atom of chlorine for a total of 2 chlorine atoms and 1 magnesium atom. This is because magnesium (Mg) has a charge of +2 and needs to lose both electrons to achieve a stable electron configuration. It pairs with two chloride ions (Cl-) to balance out the charge, which leads to the formula MgCl2. The chlorine atoms in the magnesium chloride compound are not in the diatomic Cl2 form that elemental chlorine exists in, but rather as two individual Cl- ions balancing the Mg2+ ion. The balanced chemical equation for the reaction between magnesium and chlorine gas to form magnesium chloride is Mg(s) + Cl2 (g) → MgCl2.