Question

When dating very old items, things over 100,000,000 years old, it is important that the radioisotope

A. Have a very short half-life
B. Give off light
C. Have a very long half-life
D. Not be soluble in water

Answer 1

When dating very old items, it is important to use a radioisotope with a very long half-life, such as uranium-238.

Step-by-step explanation:

When dating very old items, such as those over 100,000,000 years old, it is important that the radioisotope have a very long half-life. This is because the decay of the isotope occurs at a predictable rate, and a longer half-life allows for more accurate dating of ancient objects. One example of a radioisotope used for dating ancient objects is uranium-238, which has a half-life of 4.5 x 10^9 years.