This is what I got hope this makes sense:There is 1 mol of Mg 2+ ions in one mole of MgCl2, we can get that from the formula. Multiply 3.00 moles by 6.022x10^23 to get moles of MgCl2. There are 6.022x10^23 ions in one mole of substance. (3.00)(6.022x10^23) =1.81x10^24 Mg 2+ ions Hope it helps though
