What happens when antimatter of an atom interacts with matter of another atom? For example, if I collide antihydrogen and helium. I always heard that collision or interaction of antimatter and matter of same kind annihilate, but what about antimatter and matter of different kinds?
Assuming you mean anti 1 H hydrogen (normal hydrogen) then you would have before the reaction:
1 antielectron (or positron) 2 electrons 1 antiproton 2 protons 2 neutrons And assuming we get a nice even annihilation reaction afterwards you'd have:
1 electron 1 proton 2 neutrons lots and lots of energy in the form of gamma rays So in theory you'd get an atom of tritium (Hydrogen with two neutrons), however tritium is radioactive and tends to decay into helium-3 (helium with one less neutron than normal) plus an electron and anti-neutrino. And we also have a lot of energy from the annihilated H - anti-H. So you're more likely to have bits and pieces flying away at high speeds.