The first excitation potential of an atom refers to the energy required to promote an electron from its ground state to the first excited state. This energy is typically measured in electron volts (eV).
The ionization potential, on the other hand, refers to the minimum energy required to completely remove an electron from an atom, thus ionizing it. It represents the energy needed to remove the electron from the atom's highest occupied energy level (usually the valence shell) to an unbound state.
The ionization potential is generally greater than or equal to the first excitation potential since it involves the complete removal of an electron from the atom rather than just promoting it to an excited state.
Therefore, the ionization potential of the atom would be greater than or equal to one volt, but without more specific information about the atom in question, it is not possible to determine the exact value. Different atoms have different ionization potentials based on their electron configurations and atomic properties.