Protons # Neutrons # Electrons Element Symbol Atomic Number Mass Electrical Charge 1 0 1 8 8 8 17 18 18 36 50 36
9.Potassium-40 decays into argon-40 with a half-life of 1.2 billion years. A particular mineral grain is known to have had a million potassium atoms in its crystal structure when it formed. When the grain was ground up, scientists discovered 750,000 atoms of argon-40. When did the grain form? (Hint: Use Figure 12-10 on page 272 to obtain a qualitative estimate). 10.What are the half-lives of the following common isotopes: ?Carbon-14: ?Uranium-238: ?Uranium-235:
0 comments:
Post a Comment