Halogens don't have a single atomic number because they are a group of elements, not a single element.

The halogens are a group on the periodic table (Group 17 or VIIa) which includes:

* Fluorine (F): Atomic number 9

* Chlorine (Cl): Atomic number 17

* Bromine (Br): Atomic number 35

* Iodine (I): Atomic number 53

* Astatine (At): Atomic number 85

Each halogen has a unique atomic number, which represents the number of protons in its nucleus.