Question

The lanthanoid elements are:

Brittle and acidic
Synthetic
Soft and malleable
Unreactive

Answer 1

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Lanthanoid elements [ atomic number : 57 - 70 ] are metals that lie below transition metals in periodic table and are very reactive in nature, they are also reffered as rare earth metals, with characteristics like : they are so soft that can be even cut through by knife, and malleable as well, they are mostly paramagnatic.

so, conclusion can be made that the Correct choice is :

C. Soft and Malleable