Beryllium and magnesium do not give colour to flame whereas other alkaline eath metals do so. Why?

Explanation

### Step-by-Step Solution:

1. **Understanding Flame Colors**: When certain metals are heated in a flame, their electrons can absorb energy and get excited to higher energy levels. When these electrons return to their ground state, they release energy in the form of visible light, which is perceived as color.

2. **Properties of Beryllium and Magnesium**: Beryllium (Be) and Magnesium (Mg) are alkaline earth metals. They have relatively small atomic sizes compared to other alkaline earth metals.

3. **Ionization Energy**: Beryllium and Magnesium have high ionization energies. This means that their outer electrons are held more tightly to the nucleus compared to other alkaline earth metals.

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