* Protons define the element: The number of protons in an atom's nucleus determines what element it is.
* Chlorine (Cl) and Bromine (Br) are different elements: Chlorine has 17 protons, while Bromine has 35 protons.
* Cl2 and Br2 are diatomic molecules: They are composed of two atoms of the same element bonded together. This doesn't change the number of protons in each atom.
Therefore, Cl2 (two chlorine atoms) has 34 protons in total, and Br2 (two bromine atoms) has 70 protons in total.
