+solved @user1 @user2... to close the thread when your doubt is solved. Mention the users who helped you solve the doubt. This will be added to their stats.
As far as I can tell you have to find number of moles of Aluminium atoms and then calculate +ve charge $(Atomic-number \cdot e \cdot N_0 \cdot number-of-moles)$
still bone
gentle shard
whole yew
cerulean igloo