Question

What are inner - transition elements ? Decide which of the given atomic numbers are the number of the inner transition elements `:` 29, 59, 74,95, 102, 104.

Answer 1

The f-block elements , i.e., in which the last electron enters into f-subshells are called inner - transition elements. These include lanthanoids ( 58- 71) and actinoids ( 90 - 103) . Thus, elements with atomic numbers 59 , 95 and 102 are inner transition elements.