Base your answer on the information below. Polonium-210 occurs naturally, but is scarce. Polonium-210 is primarily used in devices designed to eliminate static electricity in machinery. It is also used in brushes to remove dust from camera lenses. Polonium-210 can be created in the laboratory by bombarding bismuth-209 with neutrons to create bismuth-210. The bismuth-210 undergoes beta decay to produce polonium-210. Polonium-210 has a half-life of 138 days and undergoes alpha decay. Determine the total mass of an original 28.0-milligram sample of Po-210 that remains unchanged after 414 days. Show the math setup, the arrows, and your answer for full credit.