Question

Total number of inner transition elements are :

Answer 1

There are $28$ inner transition elements. The inner transition elements are two series of elements known as the lanthanoids (previously called lanthanides) and actinoids (previously called actinides). They are usually shown below all the other elements in the standard view of the periodic table, but they really belong to periods $6$ and $7$. They include elements $57-71\left(14lanthanides\right)$ and $89-103\left(14actinides\right)$.