Multiatomic Elements
Most elements can be isolated as monatomic (single atom) elements. A few elements exist only as diatomic elements.
These are: hydrogen H2 oxygen O2
nitrogen N2 fluorine F2
chlorine Cl2 bromine Br2
iodine I2
I call these elements the "HOBrFINCl twins"
Two elements which exist with more than one atom per molecule are:
phosphorous P4 and sulfur S2