space for h2o clones, a to delete the clones, b to double the amount-on the labels and make them normal, up arrow to make a helium atom clone, 9 to delete the helium atom clones, d to make the amount on the labels back to 1 helium atom clone and 0 for a duplicate.
I got the idea of helium atom from an encyclopedia by Chris Woodford and Steve Parker and thanks for their periodic table. :)
