by vanceEE
 P: 109 "Radium-226 has a half-life of 1,620 years, which means that half of a given sample of radium-226 will decay into lead by the end of 1,620 years. In the next 1,620 years, half of the remaining sample will decay into lead, leaving one-fourth of the original amount of radium-226."(1) Wouldn't half of the Radium-226 decay into Radon-222 instead of Lead? I am new to this but my previous knowledge of decay from Physics tells me that Radium would would first decay to Radon by the end of 1,620 years which can be described by the equation below: $\stackrel{226}{86}Ra→ \stackrel{222}{84}Rn + \stackrel{4}{2}He$ Is (1) a misprint or am I missing the half-life concept?
 Quote by Borek I think it should be more like $$^{226}_{\phantom{0}88}Ra \rightarrow {}^{222}_{\phantom{0}86}Ba + ^{4}_{2}He$$
 Admin P: 23,601 Sigh, I copy pasted nice LaTeX from another post - and I corrected atomic masses, but got distracted and left Ba from the original code $$^{226}_{\phantom{0}88}Ra \rightarrow {}^{222}_{\phantom{0}86}Rn + ^{4}_{2}He$$
 Sci Advisor P: 3,596 :-) How about $$\mathrm{^{226}_{\phantom{0}88}Ra \rightarrow {}^{222}_{\phantom{0}86}Rn + ^{4}_{2}He}$$?