I was surprised when the speaker at todays Physics colloquium [which was on climate change] David Jamieson kept referring to Svante Arrhenius as a physicist. I always thought he was chemist! This claiming of Arrhenius as "one of our own" probably irritated me a little because the speaker made some other claims which I felt were rather debatable [perhaps more on that in another post...]. So I went and read the Wikipedia page on Arrhenius which turns out to be pretty fascinating reading [e.g. the almost failed thesis which got him the Nobel Prize! and the commitment to eugenics...].
I now concede you could argue that he was a physicist, because he seems to have done a degree in physics and mostly worked in physics institutes. However, he basically worked on and helped found what today is called physical chemistry (electrolytes and reaction kinetics). His contribution to understanding the greenhouse effect was certainly from the perspective of a physical chemist. He was awarded the Nobel Prize in Chemistry, but was a longtime member of the awards committee for physics.
Today I think Arrhenius would be classified as a physical chemist and would be in a Chemistry department.
What about other "physicists" who have received the Nobel Prize in Chemistry?
I would perhaps classify Lars Onsager as 30% per cent physicist, Alan Heeger as 60% physicist, and Walter Kohn as 99% physicist.
But, do such details really matter? Perhaps only to chemists! After all, physicists don't care about the details. Cows are spherical...