The number of elements in each of the inner transition series is

Options

A. 2
B. 8
C. 10
D. 14

Explanation

To determine the number of elements in each of the inner transition series, we need to analyze the f-block of the periodic table, which consists of two series: the lanthanoids and the actinoids.

### Step-by-Step Solution:

1. **Understanding the f-block**: The f-block elements are divided into two series: the lanthanoids (or lanthanides) and the actinoids (or actinides).

2. **Identifying the orbitals**: The f-block elements are characterized by the filling of the f-orbitals. Each f-subshell can hold a maximum of 14 electrons because there are 7 f-orbitals and each orbital can hold 2 electrons.

3. **Counting the elements**: Since each of the two series (lanthanoids and actinoids) corresponds to the filling of the f-orbitals, and since there are 14 electrons that can be accommodated in the f-orbitals, each series contains 14 elements.

4. **Listing the elements**:
- The lanthanoid series starts with Cerium (Ce, atomic number 58) and ends with Lutetium (Lu, atomic number 71).
- The actinoid series starts with Thorium (Th, atomic number 90) and ends with Lawrencium (Lr, atomic number 103).

5. **Conclusion**: Therefore, the number of elements in each of the inner transition series (both lanthanoids and actinoids) is 14.

### Final Answer:
The number of elements in each of the inner transition series is **14**.

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