The d & f Block Elements — Chemistry STD 12 Science — Question
Gujarat BoardEnglish MediumSTD 12 ScienceChemistryThe d & f Block Elements1 Mark
MCQ
Which of the following is not an actinide?
A
Uranium
B
Curium
C
Californium
✓
Erbium
✓
Answer
Correct option: D.
Erbium
Erbium with atomic number 68, electronic configuration $[\mathrm{Xe}] 4 \mathrm{f}^{12} 6 \mathrm{s}^2$ belongs to lanthanides.
$\therefore$ Erbium is not an actinide.
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