Question

The total number of inner transition elements in the modern periodic table is

• A. 10
• B. 14
• C. 28
• D. 32

Answer 1

The Correct Option is C

To determine the total number of inner transition elements in the modern periodic table, we need to understand the structure and classification of the periodic table.

1. Understanding Inner Transition Elements:
Inner transition elements are a subset of transition metals located at the bottom of the periodic table. They are divided into two series:

• Lanthanides (or Lanthanoid Series): These elements occupy the 6th period and correspond to the filling of the 4f orbitals. The lanthanide series includes elements from cerium ($\text{Ce}$, atomic number 58) to lutetium ($\text{Lu}$, atomic number 71). This series contains 14 elements.
• Actinides (or Actinoid Series): These elements occupy the 7th period and correspond to the filling of the 5f orbitals. The actinide series includes elements from thorium ($\text{Th}$, atomic number 90) to lawrencium ($\text{Lr}$, atomic number 103). This series also contains 14 elements.

2. Total Number of Inner Transition Elements:
The total number of inner transition elements is the sum of the elements in the lanthanide series and the actinide series:

$$ \text{Total} = \text{Number of Lanthanides} + \text{Number of Actinides} $$ $$ \text{Total} = 14 + 14 = 28 $$

3. Conclusion:
The total number of inner transition elements in the modern periodic table is 28.

Final Answer: $ {28} $