The relative formula mass (M_(r)) of magnesium oxide (MgO) is 40. If the relative atomic mass of oxygen is 16 , what is the relative atomic mass of magnesium?

## Step 1:We are given the relative formula mass ( ) of magnesium oxide ( ) as 40. We also know the relative atomic mass of oxygen ( ) is 16. We need to find the relative atomic mass of magnesium ( ).## Step 2:The relative formula mass of a compound is the sum of the relative atomic masses of the elements in the compound. For magnesium oxide ( ), this can be expressed as:### **\(M_r(\mathrm{MgO}) = M_r(\mathrm{Mg}) + M_r(\mathrm{O})\)**## Step 3:Substitute the given values into the formula:### **\(40 = M_r(\mathrm{Mg}) + 16\)**## Step 4:Solve for the relative atomic mass of magnesium (\(M_r(\mathrm{Mg})\)):### **\(M_r(\mathrm{Mg}) = 40 - 16\)**## Step 5:Perform the calculation:### **\(M_r(\mathrm{Mg}) = 24\)**#