Physics Nuclear Physics ETEA 2022
PMDC Verified Question 39 of 98
Which one is stable element in the followings?
A
Lead
B
Plutonium
C
Radium
D
Protactinium
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Lead


Concept:

Elements with atomic numbers \(Z > 82\) are naturally radioactive and decay continuously until they reach a stable nuclear configuration.

Solution:

  • Plutonium (\(Z=94\)), Radium (\(Z=88\)), and Protactinium (\(Z=91\)) are all heavy, highly unstable radioactive elements.


  • Lead (Pb), with an atomic number of \(Z = 82\), is the heaviest stable element. The three major natural radioactive decay series (Uranium, Actinium, Thorium) all terminate with stable, non-radioactive isotopes of Lead.


Why other options are incorrect:

Plutonium, Radium, and Protactinium lack any stable isotopes and exist in a state of continuous decay.

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