# General Chem question help!

#### JMC114

10+ Year Member
Question: What is the mass in grams of a single chlorine atom?

Answer: (35g)/(6.022 X 10^23 molecules) = 5.81x10^-23 g/atom

But shouldn't it be 70g not 35g because Cl is a diatomic molecule?

#### sddat

10+ Year Member
5+ Year Member
Question: What is the mass in grams of a single chlorine atom?

Answer: (35g)/(6.022 X 10^23 molecules) = 5.81x10^-23 g/atom

But shouldn't it be 70g not 35g because Cl is a diatomic molecule?

it's asking for a single chlorine atom. It's true that the halogens usually exist as diatomic molecules, but this question isn't asking for that. They don't ALWAYS exist (theoretically) as diatomic particles. They are just likely to exist experimentally as diatomic particles. I could be wrong, but that's how I understood that topic.

#### Sublimation

10+ Year Member
5+ Year Member
Question: What is the mass in grams of a single chlorine atom?

Answer: (35g)/(6.022 X 10^23 molecules) = 5.81x10^-23 g/atom

But shouldn't it be 70g not 35g because Cl is a diatomic molecule?

The reason its not is because as ur solution, which is right illustrates, its the mass per atom, and the question clearly states "mass of a single chlorine ATOM" which u solved correctly. Yes Cl does usually exist as a diatomic molecule, but thats a molecule. Chlorine also exists as a anion.

#### JMC114

10+ Year Member
Great explanation, thanks for your help!

#### JMC114

10+ Year Member
The reason its not is because as ur solution, which is right illustrates, its the mass per atom, and the question clearly states "mass of a single chlorine ATOM" which u solved correctly. Yes Cl does usually exist as a diatomic molecule, but thats a molecule. Chlorine also exists as a anion.
Great explanation, thanks for your help!