The ionisation energy of hydrogen is high as compared to alkali metals because of

Explanation

To understand why the ionization energy of hydrogen is high compared to alkali metals, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Definition of Ionization Energy**:
- Ionization energy is the energy required to remove an electron from an atom in its gaseous state.

2. **Position of Hydrogen and Alkali Metals**:
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