Out of the following elements,which one is the most reactive chemically?

Options

A. Ba
B. Sr
C. Ca
D. Mg

Answer

To determine which of the given elements is the most chemically reactive, we need to analyze the reactivity of the elements listed. The elements mentioned are beryllium, magnesium, calcium, and possibly others that were not clearly stated in the transcript. However, we will focus on the alkaline earth metals mentioned.

### Step-by-Step Solution:

1. **Identify the Elements**: The elements in question are beryllium (Be), magnesium (Mg), and calcium (Ca). These elements belong to the alkaline earth metals group in the periodic table.

2. **Understand Reactivity Trends**: In the periodic table, the reactivity of alkaline earth metals increases as you move down the group. This is because:
- As you go down the group, the atomic size increases.
- The outer electrons are farther from the nucleus and are less tightly held due to increased shielding effect.
- This makes it easier for these elements to lose their outermost electrons and react with other substances.

3. **Compare the Elements**:
- **Beryllium (Be)**: Located at the top of the alkaline earth metals group, it is less reactive compared to the others.
- **Magnesium (Mg)**: More reactive than beryllium but less reactive than calcium.
- **Calcium (Ca)**: Located below magnesium, it is more reactive than both beryllium and magnesium.

4. **Conclusion**: Since calcium is the lowest in the group and has the highest reactivity among the elements listed, it is the most chemically reactive element.

### Final Answer:
The most reactive element among the ones listed is **Calcium (Ca)**.