Question

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.

Answer 1

In the periodic table, there are the elements that are partially filled with d and f subshells. D-block elements are called transition elements and f-block elements are inner transition elements. Inner transition elements are the core metals of the transition.

Complete answer:

Lanthanides and actinides are the two groups of elements that are present in the periodic table. There total 30 elements in these two groups and collectively known as inner transition elements. Inner transition elements are also known as f-block elements.
Lanthanides and actinides are the 4f and 5f series of the inner transition elements. Uranium, thorium, and protactinium is a good source of nuclear energy. Lanthanide series contain atomic numbers from 57 to 71 whereas actinides series having 89 to 103 atomic numbers.
Inner transition elements form coloured ions, the third last shell is filled with the electrons and they show variable valencies. The inner transition elements beyond 92 up to 103 are radioactive as well as synthetic in nature. They are found in the earth’s crust.
Thus, the elements with atomic number 59, 95 and 102 are the inner transition elements and the rest of the atomic numbers are not the inner transition elements.

Note: Lanthanides and actinides are listed below the periodic table’s main section. They have valence electrons. All actinides are toxic and can be used as a weapon. They have no commercial value.