Radium-226 is a common isotope on Earth, but has a half-life of ...

[armygirl]

Radium-226 is a common isotope on Earth, but has a half-life of about 1600 years. Given that Earth is some 5 billions years old, why is there any radium at all?
 
  A) Radium-226 is one of several self-transmutating isotopes of the elements of the periodic table and is able to replenish itself so that it is never depleted.
  B) Radium-226 and Radium-218 undergo a series of transmutation reactions of alpha and beta decay to repeatedly become one another approximately every 1600 years.
  C) Radium-226 is a daughter isotope and the result of the radioactive decay of uranium.
  D) Radium-226 and Astatine-218 are converted back and forth via transmutation to one another at each of their respective half-life cycles.

Question 2

What chemical change occurs when a wax candle burns?
 
  A) The wax near the flame melts.
  B) The molten wax is pulled upwards through the wick.
  C) The wax within the wick is heated to about 600C.
  D) The heated wax molecules combine with oxygen molecules.

[C.mcnichol98]

Answer to Question 1

C

Answer to Question 2

D

[armygirl]

Gracias!

[amcvicar]

Excellent