Calculate the ionisation energy in eV of a hydrogen atom in the ground state.

Explanation

To calculate the ionization energy of a hydrogen atom in the ground state, we can follow these steps:

### Step 1: Understand the Ionization Energy Concept
Ionization energy is the energy required to remove an electron from an atom in its gaseous state. For hydrogen, we will use the Bohr model to find this energy.

### Step 2: Use the Formula for Energy of the n-th Bohr Orbit
The energy of an electron in the n-th orbit of a hydrogen atom is given by the formula:
\[ E_n = -\frac{13.6 \, \text{eV}}{n^2} \]
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