3 2 2 3 2 5 2 5 Moist O H O I HIO O -> 3 2 2 2 2 2 Colloidal FeCl H S FeCl HCl S -> 3 2 2 2 Black O Ag Ag O O ->
Take chapter-wise tests, track your progress, and master p -Block Elements (group 15-18).