Radioactive+Decay+Constants

N=Nitrogen K= Potassium Ar = Argon Ca = Calcium Pb = Lead Sr = Strontium

This chart is used for determining the age of materials. The process uses the decay of naturally occurring radioactive isotopes into more stable elements.

The name of the isotope is followed by a number. Carbon-14 means that the atomic weight of this carbon is 14 amu (__a__tomic __m__ass __u__nits), we refer to this then as Carbon 14. Non-radioactive carbon is Carbon-12, or carbon with an atomic mass of 12 amu.

Information about elements can be found on the Periodic Table of Elements.

When Carbon-14 decays, it releases energy and becomes Nitrogen-14 (N 14 on the chart).

The half-life is how long it takes 1/2 of a sample of Carbon-14 to become Nitrogen-14 (C 14 ---> N 14 ) it will take 5.7 x 10 3 years for this to happen, or 5700 years.

If you have an 8 gram sample of C 14, by the time 5700 years passes, your sample will be 4 g of C 14 and 4 g or N 14. You have cut the amount of C 14 in half.

After another half life, the 4 grams will now be 2 grams, and so on.


 * Half-Life || Mass(g) of C 14 || Mass (g) N 14 ||
 * 0 || 8 || 0 ||
 * 1 || 4 || 4 ||
 * 2 || 2 || 6 ||
 * 3 || 1 || 7 ||
 * 4 || 0.5 || 7.5 ||
 * 5 || 0.25 || 7.75 ||
 * 6 || 0.125 || 7.875 ||

Typical questions and how to solve