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The d & f Block Elements — Chemistry STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceChemistryThe d & f Block Elements1 Mark
MCQ
The only radioactive element among the lanthanoids is:
  • A
    Gadolinium.
  • B
    Holmium.
  • C
    Promethium.
  • D
    Neodynium.
✓

Answer

  1. Promethium.

Explanation:

Promethium is a lanthanoid element with the symbol Pm and atomic number 61. All of its isotopes are radioactive. Gadolinium, holmium and neodynium are lanthanoids but are not radio active.

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