Which of the following donot impart colour to the flame ?

Options

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

Answer

To determine which elements do not impart color to the flame, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Flame Coloration**:
- When an element is heated, its electrons can absorb energy and move to higher energy levels. When these electrons return to their original levels, they emit energy in the form of light (photons), which can be observed as color in the flame.

2. **Identifying the Elements**:
- The question asks us to identify which of the given elements do not impart color to the flame. In this case, we will focus on Beryllium (Be) and Magnesium (Mg).

3. **Analyzing Beryllium and Magnesium**:
- Both Beryllium and Magnesium have relatively small atomic sizes. This small size leads to a high ionization enthalpy, which is the energy required to remove an electron from an isolated gaseous atom.

4. **Understanding Ionization Enthalpy**:
- Since Beryllium and Magnesium have high ionization enthalpy, it means that a significant amount of energy is needed to remove their electrons. As a result, they do not lose electrons easily when heated.

5. **Conclusion**:
- Because Beryllium and Magnesium do not lose electrons easily, they do not get excited to higher energy levels and, therefore, do not emit photons of different wavelengths. This is why they do not impart color to the flame.

### Final Answer:
Beryllium and Magnesium do not impart color to the flame.

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