Final answer:
The metal in the compound MCl2 is Magnesium (Mg).
Step-by-step explanation:
The compound MCl2 contains 57.69% Cl by mass. To identify the metal in the compound, we need to determine the molar mass of Cl and find the metal that forms a compound with a molar mass equal to the compound's formula weight.
The molar mass of Cl is 35.45 g/mol. To find the molar mass of the compound, we can sum the molar masses of one Cl atom (35.45 g/mol) and two Cl atoms (70.91 g/mol). Since the compound's formula weight is equal to 70.91 g/mol, the metal in the compound is Magnesium (Mg), giving us the symbol Mg as the answer.