Do antiparticles exhibit different chemical properties?

Question

In my physics class today. My teacher mentioned anti-helium and since I had never heard of anti-atoms (if you get what I mean by that) just antiparticles, this made me think: If we could produce anti-helium in our world without it being annihilated by helium, would it still exhibit the same chemical properties? (i.e. floating upwards or making anti-isotopes)

Answer 1

Whether antichemistry is different from matter chemistry is an experimental question which has not been resolved. We predict that the behaviors of matter versus antimatter atoms should be substantially identical. A better phrasing might be that we predict differences between chemistry versus antichemistry would require high-precision measurements to observe.

We know that antimatter and matter do not interact among themselves in quite identical ways. These differences are based on two lines of evidence, from opposite ends of the experimental spectrum. Subatomic experiments show that some interactions, decays, et cetera are different depending on whether the participants are matter or antimatter. These experiments are usually described as measurements of "CP violation," where a "CP transformation" is the mathematical tool which switches between matter and antimatter in the Standard Model. At the other end, we have the observation that the Universe contains lots of matter but only incidental antimatter. This asymmetry not only confirms that there must be differences between matter versus antimatter interactions, but also predicts that we have not yet found enough CP violation in subatomic physics to explain the matter fraction of the universe.

The first precision measurement of the atomic antihydrogen spectrum was published in 2017. The spectrum was identical to the matter hydrogen spectrum within the precision of the experiment (as predicted).

Answer 2

No. Chemical reactions and some physical properties are determined by the electron structure for normal matter, and symmetrically the same for positron in antimatter. So chemical reactions between antimatter would appear similar in every respect as normal matter behaves.

Of course mixing matter with antimatter leads to a much different result, with the reaction not being chemical, but rather annihilation.