The half-life of bismuth-210, 210bi, is 5 days. (a) if a sample has a mass of 160 mg, find the amount remaining after 15 days. mg

solution:

The general form of the equation would be A = P x  (1/2) ^ (t/h) where A = final amount, P = start amount, t = time (here in days) and h = half-life (has to be same units as t)  

a) A = 192 x (1/2) ^ (15/5) = 192 x (1/2) ^3 = 192 x 1/8 = 24 mg

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

ill try to . no promises tho.

explanation: