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The number of elements from the following that do not belong to lanthanoids is Eu, Cm, Er, Tb, Yb and Lu
(2) 1
Lanthanoids: the 4f series, Ce (Z = 58) to Lu (Z = 71)
Eu (63), Tb (65), Er (68), Yb (70), Lu (71) ⇒ all 4f ⇒ lanthanoids
∵ Cm (Z = 96) fills 5f ⇒ Cm is an actinoid
∴ only 1 element (Cm) is not a lanthanoid
Answer: (2)
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