Which one of the following is an s-block element?

Options

A. Aluminium
B. Chromium
C. Niobium
D. Potassium

Answer

To determine which of the given elements is an s-block element, we can follow these steps:

### Step 1: Understand the s-block elements
The s-block elements are found in Group 1 and Group 2 of the periodic table. Group 1 includes alkali metals, and Group 2 includes alkaline earth metals. The elements in these groups have their outermost electrons in s orbitals.

### Step 2: Identify the given elements
The elements provided in the question are:
- Aluminium (Al)
- Chromium (Cr)
- Niobium (Nb)
- Potassium (K)

### Step 3: Determine the group of each element
- **Aluminium (Al)**: This element is in Group 13 (p-block).
- **Chromium (Cr)**: This element is in Group 6 (d-block).
- **Niobium (Nb)**: This element is in Group 5 (d-block).
- **Potassium (K)**: This element is in Group 1 (s-block).

### Step 4: Conclusion
Among the given options, **Potassium (K)** is the only s-block element.

### Final Answer:
Potassium (K) is an s-block element.

---