The Potassium-Argon dating method is the measurement of the accumulation of Argon in a mineral. It is based on the occurrence of a small fixed amount of the radioisotope 40K in natural potassium that decays to the stable Argon isotope 40Ar with a half-life of about 1,300 million years.
How long does it take for ½ of potassium to turn into argon 40?
1) Potassium-40 is an unstable atomic nucleus; it decays to Argon-40 with a half-life of 1.3 bil- lion years. Suppose that a rock contains 1,000 Potassium-40 atoms at the time it forms.
What percentage of C 14 remains after 3 half lives?
After 1 half-life, 12 of the C-14 would remain. After 2 half-life, 12 of the 12 of the C-14 = 14 of the C-14 would remain. After 3 half-life, 12 of the 14 of the C-14 = 18 of the C-14 would remain.