How many polonium atoms decay per day from 1 million atoms?

Problem data: N0 (initial number of polonium atoms) = 1 * 106 atoms; t (elapsed time from the beginning of decay) = 1 day.

Reference values: T (half-life of polonium-210) = 138 days 9 hours = 138.375 days.

1) The number of non-decayed atoms of polonium-210: N = N0 * 2 -t / T = 1 * 10 ^ 6 * 2 -1 / 138.375 = 0.995 * 106 atoms.

2) The number of decayed atoms: N1 = N – N0 = 1 * 10 ^ 6 – 0.995 * 10 ^ 6 = 5000 atoms.

Answer: 5000 atoms of polonium-210 will decay in 1 day.