The pair of most abundant alkali metals is ?

Options

A. Li & Na
B. Na & K
C. K & Rb
D. Na & Rb

Answer

To determine the pair of most abundant alkali metals, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Alkali Metals**:
Alkali metals are found in Group 1 of the periodic table. The alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).

2. **Understand Abundance**:
The term "most abundant" refers to the elements that exist in the largest quantities in nature. This can be measured by their abundance in the Earth's crust or in seawater.

3. **Research Abundance of Alkali Metals**:
Among the alkali metals:
- Lithium is relatively rare and is the 34th or 35th most abundant element.
- Sodium is much more abundant, ranking as the 7th most abundant element.
- Potassium follows closely, being the 8th most abundant element.
- Rubidium and cesium are less abundant, and francium is radioactive and extremely rare.

4. **Identify the Most Abundant Pair**:
Based on the abundance rankings, sodium (Na) and potassium (K) are the two most abundant alkali metals. They are commonly found in nature, particularly in seawater and various minerals.

5. **Conclusion**:
Therefore, the pair of most abundant alkali metals is sodium (Na) and potassium (K).

### Final Answer:
The pair of most abundant alkali metals is sodium (Na) and potassium (K).

---