The ionization energy of hydrogen atom in the ground state is

The ionization energy of an atom is the minimum energy required to remove an electron from its ground state to an infinite distance from the nucleus. According to the Bohr model, the energy levels of a hydrogen atom are defined by the formula E = -13.6/n² eV, where 'n' is the principal quantum number. In the ground state (n = 1), the energy of the electron is -13.6 eV. To ionize the atom, the electron must be transitioned to a state where its energy is zero (n = ∞). Therefore, the energy required for this transition is 0 - (-13.6 eV) = 13.6 eV. While this energy can be expressed in Joules (approximately 2.18 × 10⁻¹⁸ J), the standard value provided in the options is 13.6 eV. Option 1 is incorrect as MeV (Mega-electronvolts) represents a much higher energy scale.