HCl is a molecule, not an atom, so it doesn't have an atomic number.

Here's why:

* Atomic Number: The atomic number refers to the number of protons in an atom's nucleus. It's a fundamental property of an element.

* HCl: HCl stands for hydrogen chloride, a compound formed by the covalent bonding of one hydrogen atom (H) and one chlorine atom (Cl).

Individual atomic numbers:

* Hydrogen (H): Atomic number 1

* Chlorine (Cl): Atomic number 17