If a radioactive isotope of thorium (atomic number 90, mass number 232) emits 4 alpha particles and 2 beta particles during the course of radioactive decay, what are the atomic number and mass number of the stable daughter product?

The half-life of 1311 is 8.04 days. (a) Convert the half-life to seconds. S (b) Calculate the decay constant for this isotope. S-1 (c) Convert 0.570 μCi to the SI unit the becquerel. Bq (d) Find the number of 13¹1 nuclei necessary to produce a sample with an activity of 0.570 μCi. 1311 nuclei (e) Suppose the activity of a certain 13¹1 sample is 6.90 mCi at a given time. Find the number of half-lives the sample goes through in 40.2 d and the activity at the end of that period. (Enter your answer for the number of half-lives to at least one decimal place.) half-lives mCi

11. Radium-226, 226Ra, undergoes an alpha decay. The current sample of Radium-226 has an initial activity of 5.50 × 101º Bq. (a) Identify the daughter nucleus by name, nucleon number, atomic number and neutron number. (b) What is the decay constant? (c) How many radioactive nuclei were initially present in the sample? (d) How long will it take the sample to reach an activity of 5.00 x 1010 Bq?