Because the reduced mass of muonium, and hence its Bohr radius, is very close to that of hydrogen, this short-lived " atom " ( or a muon and electron ) behaves chemically to a first approximation like the isotopes of hydrogen ( protium, deuterium and tritium ).
12.
"' 2004 "' University of Toronto becomes a full member, Saint Mary's University becomes an associate member, Seaborg Award to Don Fleming for pioneering work in muonium, charge radius of 11 Li measured, T2K collaboration with J-PARC begins, Synergy Award for collaboration between TRIUMF and Nordion
13.
Other systems may also be referred to as " hydrogen-like atoms ", such as muonium ( an electron orbiting a muon ), positronium ( an electron and a positron ), certain exotic atoms ( formed with other particles ), or Rydberg atoms ( in which one electron is in such a high energy state that it sees the rest of the atom practically as a point charge ).
