Does Cl2 (chlorine) have a -2 charge or -4 charge since there are 2 of them?
Neither. All elements in the free state have a zero charge.
To determine the charge of an element in a compound, you need to consider its oxidation state. In the case of chlorine (Cl2), it exists as a diatomic molecule, which means two chlorine atoms are bonded together.
When chlorine is in its elemental state (Cl2), its oxidation state is zero. This means each individual chlorine atom in Cl2 has an oxidation state of zero, and therefore carries no charge.
The overall charge of Cl2 is determined by the combining elements or ions in the compound. In this case, Cl2 exists as a neutral molecule with no charge because the two chlorine atoms have equal but opposite oxidation states, cancelling out any charge.
So, chlorine in Cl2 does not have a -2 or -4 charge. Each chlorine atom has an oxidation state of zero, and the compound as a whole is neutral.