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

Explanation

The f - block elements i.e., the elements in which the last electron enters into f - subshell are called inner transition elements. There are two series of inner transition elements : 4f - series (i.e., lanthanoids from atomic number 58 to 71) and 5f - series (i.e., actinoids from atomic number 90 to 103). Thus the elements with atomic numbers 59, 95 and 102 are inner transition elements.