MCQ Detailed View

The most stable element among the given options is Lead (Pb), particularly the isotope Lead-208. It is widely known in nuclear chemistry for its exceptional stability. Lead-208 has a “magic number” of protons and neutrons — a term used in nuclear physics to describe numbers that result in completely filled nuclear shells, making the nucleus highly stable.

Let’s briefly look at each option:

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  Uranium is a radioactive element. It undergoes nuclear decay, especially Uranium-235 and Uranium-238. These isotopes are used as fuel in nuclear reactors but are not stable naturally.

  
  


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  Hydrogen, while the simplest and most abundant element, is not considered the most stable in terms of nuclear or atomic structure. Its single proton nucleus is stable, but compared to lead, it doesn’t meet the criteria for nuclear stability.

  
  


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  Oxygen is an essential and reactive element. Its nucleus is stable in common isotopes like Oxygen-16, but again, it is more chemically reactive than lead and doesn't have the nuclear “magic numbers.”

  
  


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  Lead, especially isotope Pb-208, is the end product of many radioactive decay chains (like uranium and thorium series). Because of this, it is considered a final, stable form in nature. It does not undergo radioactive decay further.

  
  

This stability makes lead important in shielding radioactive materials and in studies of nuclear structure. Its heavy atomic mass and full nuclear shells contribute to its role as a "closed chapter" in nuclear decay processes.

In conclusion, Lead is the most stable element among the given options due to its closed nuclear structure and resistance to radioactive decay.