Lanthanum is

Options

A. s-block elements
B. p-block elements
C. d-block elements
D. f-block elements

Answer

To solve the question "Lanthanum is," we need to determine the correct classification of Lanthanum based on its properties and position in the periodic table. Here’s a step-by-step breakdown:

### Step 1: Identify the Element
- **Lanthanum** is a chemical element with the symbol **La** and an atomic number of **57**.

### Step 2: Determine the Block of the Element
- Elements in the periodic table are categorized into different blocks based on their electron configurations: **s-block**, **p-block**, **d-block**, and **f-block**.
- Lanthanum has a partially filled **f-orbital**, which categorizes it as an **f-block element**.

### Step 3: Understand the Position in the Periodic Table
- Lanthanum is the first element in the **lanthanide series**, which is a group of 15 elements from Lanthanum (La) to Lutetium (Lu) in the f-block of the periodic table.
- The lanthanides are typically placed at the bottom of the periodic table, along with the actinides.

### Step 4: Confirm the Classification
- According to the **IUPAC** (International Union of Pure and Applied Chemistry), Lanthanum is classified as an **f-block element**. This classification has been recognized in recent updates to the periodic table.

### Conclusion
- Based on the above analysis, the correct answer to the question "Lanthanum is" is that **Lanthanum is an f-block element**.

### Final Answer
**Lanthanum is an f-block element.**

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