Diatomic Molecules. Some atoms are always found as

Seven Diatomic Elements
H2, O2, N2, F2, Br2, I2, Cl2
You should know that the following elements exist as diatomic
molecules. One acronym that is used is like a person’s name… HON F
BrICl (With HON being the first name, F being the middle initial,
and BrICl being the last name)
Hydrogen H2
Oxygen O2
Nitrogen N2
Fluorine F2
Chlorine Cl2
Bromine Br2
Iodine I2
Note: The fact that these elements are diatomic only relates to
these elements as isolated, neutral atoms. For instance, chlorine
when in a compound can be NaCl or CaCl2 or AlCl3. The number of
chlorine atoms depends on the charge of the atom with which the
chlorine is paired.