Drag 12 elements into three bins: metal, nonmetal and metalloid. You can also tap an element, then tap a bin.
Metals are on the left side and below the staircase.
Nonmetals are on the right side.
Metalloids touch the staircase.
Select an element. Its square is ringed on the small table.
Keyboard: Tab to an element and press Enter, then Tab to a bin and press Enter. Or press 1, 2 or 3 for Metal, Nonmetal or Metalloid.