Name the first three isotopes of hydrogen and their nuclide ...

[Diane]

Name the first three isotopes of hydrogen and their nuclide symbols, and indicate which is most common and which is most unstable.
 
  What will be an ideal response?

Question 2

If a nuclide has a decay constant of 0.765  10-6 s-1 and contains 3.0  1017 nuclei
 
  (a) what is the half life?
  (b) what is its initial activity?
  (c) what is the activity after 12. days?

[meltdown117]

Answer to Question 1

ordinary hydrogen 1H , deuterium 2H , and tritium 3H ; 1H being most common and 3H most unstable decaying with a 12. year half life.

Answer to Question 2

(a) 9.06  105 s
(b) 2.3  1011 decays/s
(c) 1.0  1011 decays/s