(Mass, decay constant and activity of a long-lived isotope)
Radium-226 has an atomic mass of 226 g mol−1 and a half-life of 1600 years. A sealed capsule contains 0.50 mg of pure 226Ra.
(i) Calculate the initial number of nuclei present in the capsule.
(ii) Determine the decay constant of 226Ra in yr−1.
(iii) Find the mass of 226Ra that will remain undecayed after 4800 years.
(iv) Compute the activity of the sample at the end of 4800 years.