Uranium-235 is best described as

Uranium-235 is best described as

• A. An unstable, fissionable isotope of uranium
• B. A stable isotope of uranium
• C. A non-radioactive metal
• D. A renewable energy resource

Answer: (A)

Isotopes can be stable or radioactive, and Uranium-235 has 92 protons and 143 neutrons in its nucleus, which makes it unstable and radioactive. That instability is what allows it to undergo fission when it captures a neutron, splitting into lighter pieces and releasing energy and more neutrons. Because it can sustain a chain reaction, Uranium-235 is fissionable (and effectively fissile with slow neutrons), which is why it’s used as nuclear fuel. It isn’t a stable, non-radioactive metal, and uranium is not considered a renewable energy resource. So the description that fits best is an unstable, fissionable isotope of uranium.

Isotopes can be stable or radioactive, and Uranium-235 has 92 protons and 143 neutrons in its nucleus, which makes it unstable and radioactive. That instability is what allows it to undergo fission when it captures a neutron, splitting into lighter pieces and releasing energy and more neutrons. Because it can sustain a chain reaction, Uranium-235 is fissionable (and effectively fissile with slow neutrons), which is why it’s used as nuclear fuel. It isn’t a stable, non-radioactive metal, and uranium is not considered a renewable energy resource. So the description that fits best is an unstable, fissionable isotope of uranium.