4-f series start from

Options

A. La to Lu
B. Ce to Lu
C. Gd to Lu
D. Pr to Lu

Answer

To determine where the 4f series starts, we need to focus on the lanthanide series, which consists of elements that have their electrons filling the 4f subshell.

### Step-by-Step Solution:

1. **Identify the Lanthanide Series**: The lanthanide series consists of 15 elements that range from Cerium (Ce) to Lutetium (Lu).

2. **Locate the Starting Element**: The 4f series begins with Cerium (Ce). This is the first element in the lanthanide series.

3. **Electron Configuration of Cerium**: The electron configuration of Cerium is [Xe] 4f¹ 5d¹ 6s². This shows that the first electron enters the 4f subshell.

4. **List of Lanthanides**: The elements in the lanthanide series are:
- Cerium (Ce)
- Praseodymium (Pr)
- Neodymium (Nd)
- Promethium (Pm)
- Samarium (Sm)
- Europium (Eu)
- Gadolinium (Gd)
- Terbium (Tb)
- Dysprosium (Dy)
- Holmium (Ho)
- Erbium (Er)
- Thulium (Tm)
- Ytterbium (Yb)
- Lutetium (Lu)

5. **Conclusion**: The 4f series starts from Cerium (Ce) and ends with Lutetium (Lu).

### Final Answer:
The 4f series starts from **Cerium (Ce)**.