Solved UPSC CDS/OTA Question
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Q · Classification of Elements Easy · 45s
Lanthanides and actinides belong to which block?
TopicClassification of Elements
Question Typemultiple choice
DifficultyEasy
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
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Every step explained - no skipped algebra.
Their valence electrons fill f-orbitals, so they are f-block elements.
Final Answer: Option D - f-block