Which of the following statements is/are CORRECT?

1. Naturally occurring isotopes account for only a small fraction of known radioactive isotopes.
2. A few radioactive isotopes with long half-lives, such as U-235 and U-238, are found in nature.
3. Trace quantities of some short-lived radioactive isotopes, such as C-14, are found in nature because they are formed continuously by nuclear reactions.
a. 1 only
b. 2 only
c. 3 only
d. 1 and 2
e. 1, 2, and 3

answer D

I think 3 is right so it can't be D.

A rock has 76% of its radioactive isotopes. Is it young or old explain

To determine which statement or statements are correct, let's analyze each statement.

1. Statement 1: "Naturally occurring isotopes account for only a small fraction of known radioactive isotopes."

To assess the accuracy of this statement, we need to understand the difference between naturally occurring isotopes and radioactive isotopes.

Isotopes are atoms of the same element that have different numbers of neutrons. These different forms are referred to as isotopes. Some isotopes are stable, meaning they do not undergo radioactive decay, while others are radioactive and eventually decay into other elements.

Naturally occurring isotopes are stable isotopes that are present in nature. Radioactive isotopes, on the other hand, are isotopes that undergo radioactive decay and are not stable.

If we consider the total number of known radioactive isotopes (both naturally occurring and artificially created), it is true that naturally occurring isotopes only make up a small fraction of this total. Therefore, statement 1 is correct.

2. Statement 2: "A few radioactive isotopes with long half-lives, such as U-235 and U-238, are found in nature."

U-235 and U-238 are isotopes of uranium. U-235 is used for nuclear power generation and weapons, while U-238 is used for various purposes, including the production of plutonium-239. Both U-235 and U-238 have long half-lives and are found in nature. Therefore, statement 2 is correct.

3. Statement 3: "Trace quantities of some short-lived radioactive isotopes, such as C-14, are found in nature because they are formed continuously by nuclear reactions."

C-14 is a radioactive isotope of carbon with a half-life of approximately 5730 years. It is constantly being formed in the Earth's atmosphere by cosmic ray interactions with nitrogen, and it is taken up by living organisms through the carbon cycle. Therefore, statement 3 is correct.

Based on the analysis of each statement, we can conclude that statements 1, 2, and 3 are all correct. Therefore, the correct answer is option e) 1, 2, and 3.