Question

Radioactive Isotope #1: Uranium-238   

1. How long is its half-life?

2. How long will it take the original radioactive product to reduce by 50%?

3. How long will it take the original radioactive product to reduce by 25%?

4. What material is the best application for this isotope?

5. Describe the disadvantages and advantages of using this element for dating.

6. What is the stable daughter product?

Answer 1

the Half-life of uranium -238 is 4.5 billion years.
as half life of the uranium-238 is 4.5 billion years, it will take 4.5 billion years i.e one half-life to reduce by 50% of original radioactive product
to decay to 25% of parent atoms, a isotope will take 2 half lifes so it will take 9 billion years to reduce to 25% of original radioactive product.
igneous rocks are best application for these materials as most of these rocks contain radio active isotopes.
advantages of using these isotope is that this isotope has absolute half life so by using this we can caliculate age of rocks or materials more accurately and due it's long half-life we can caliculate age of rocks upto long back. disadvantage is that all most all these uranium atoms found in igneous rocks and fossils are almost never found in igneous rocks, so it can't be directly use to date fossils.
Lead-206 is stable isotope of uranium-238.