The half life of radium 1640 years and its atomic weight is 227 kg per kilo mol. The number of atom’s that will decay from its 1 gm sample per minute will be

Rate of Decay, dNdt=λN where λ=0.6931t1/2=0.69311640×365×24×60 and N=mM×NA=1227×6.023×1023  Hence, dNdt=0.6931×6.023×10231640×365×24×60×227=2.1334×1012 per min