The half life of a scandium-46 is 84 days. The scandium-46<span> is used in oil refining as a tracer to monitor the oil movement and it emits </span><span>extremely high energetic gamma/beta radiation. So the half-life of the radioisotope scandium-46 is 84 days. The </span>Scandium 46 created by neutron activation, is a synthetic isotope of Scandium.
The answer is critical mass with no doub t
Potassium (K), Sodium(Na), Iron(Fe), Copper(Cu), Silver(Ag), Tin(Sn), Antimony(Sb), Tungsten(W), Gold(Au), Mercury(Hg), Lead(Pb)