I have partitioned the chemical elements into two groups based on a certain occult property that is shared by some of them, but not by the remaining ones.
The following elements have my occult property:
arsenic, astatine, carbon, iron, krypton, neon, phosphorus, silicon, tin
The following elements do not have my occult property:
antimony, boron, cobalt, germanium, gold, helium, lead, mercury, sulfur
Which of the following elements have this occult property?
aluminium, fluorine, francium, gallium, oxygen, polonium.