Question

Which element has the atomic number 92? A) Uranium B) Plutonium C) Neptunium D) Radon

Answer 1

Answer: A) Uranium

Explanation:

The element with atomic number 92 is Uranium. The atomic number represents the number of protons present in the nucleus of an atom, which uniquely identifies each element on the periodic table.

Uranium is a naturally occurring radioactive element that belongs to the actinide series. It was discovered in 1789 by German chemist Martin Heinrich Klaproth and named after the planet Uranus. With 92 protons in its nucleus, uranium is one of the heaviest naturally occurring elements on Earth.

Let's examine why the other options are incorrect:

• Plutonium (Pu) has atomic number 94, making it heavier than uranium. It's an artificially produced element that doesn't occur naturally in significant quantities.

• Neptunium (Np) has atomic number 93, placing it between uranium and plutonium on the periodic table. It's also a synthetic element.

• Radon (Rn) has atomic number 86, making it lighter than uranium. It's a noble gas that occurs naturally as a decay product of radium.

Uranium is particularly significant because of its role in nuclear energy and nuclear weapons. It has several isotopes, with U-238 being the most common (99.3% of natural uranium) and U-235 being the fissile isotope used in nuclear reactors and weapons. Understanding atomic numbers is crucial for identifying elements and predicting their chemical properties, as elements with the same atomic number belong to the same element regardless of their mass number or isotope.