Radon-222 gas can be found seeping from granite that contains uranium-238. Radon-222 is a nuclide in the radioactive decay series of uranium-238. Radon is an element with a half-life of 3.82 days.

a. Predict the most likely particle emitted when radon- 222 undergoes nuclear decay and write the nuclear equation for the decay.

b. What is the decay constant (k) for radon-222.

c. The U.S. Environmental Protection Agency recommends that the concentration of radon gas in dwellings not exceed 4 piCi per liter of air. What mass of Rn-222 would be in a 1-L sample of air that had a decay rate of 4 piCi?