B. Which of these four radioactive elements would you choose to date a specimen from the most recent epoch? (5 points)

\begin{tabular}{|l|l|}
\hline
Element & Half-life \\
\hline
Uranium-238 & 4.47 billion years \\
\hline
Potassium-40 & 1.25 billion years \\
\hline
Uranium-235 & 700 million years \\
\hline
Carbon-14 & 5,730 years \\
\hline
\end{tabular}



Answer :

To determine which radioactive element is best suited for dating a specimen from the most recent epoch, we need to consider the half-lives of the elements listed and select the one with the shortest half-life. The half-life of a radioactive element is the time it takes for half of a sample to decay. For dating recent specimens, an element with a shorter half-life will provide more accurate results.

Here are the half-lives of the given elements:
1. Uranium-238: 4.47 billion years
2. Potassium-40: 1.25 billion years
3. Uranium-235: 700 million years (or 0.7 billion years)
4. Carbon-14: 5,730 years

To determine the most appropriate element for dating recent specimens, we compare these half-lives:

1. Uranium-238 has a half-life of 4.47 billion years, which is much too long for dating recent specimens.
2. Potassium-40 has a half-life of 1.25 billion years, which is also too long for dating recent specimens.
3. Uranium-235 has a half-life of 700 million years. This is still too long for dating recent specimens.
4. Carbon-14 has a half-life of 5,730 years. This short half-life makes it the most suitable for dating recent specimens from the most recent epoch.

By comparing these half-lives, we see that Carbon-14 has the shortest half-life of 5,730 years. Therefore, Carbon-14 is the most appropriate choice for dating a specimen from the most recent epoch.

Thus, the element you should choose to date a specimen from the most recent epoch is Carbon-14, with a half-life of 5,730 years.