Ionisation Energy and Electron Affinity Ionisation energy: The energy required to remove an electron from an atom or molecule. It is the energy necessary...
Ionisation energy: The energy required to remove an electron from an atom or molecule. It is the energy necessary to ionise the atom or molecule, meaning to break it into its individual ions.
Electron affinity: The energy released when an electron is added to an atom or molecule. It is the energy gained when the atom or molecule gains a negatively charged electron.
Ionisation energy and electron affinity are closely related. Ionisation energy is the opposite of electron affinity, as it is the energy required to remove an electron from the atom or molecule.
Examples:
The ionization energy of an atom in a neutral state is the energy required to remove the outer electron, resulting in a positively charged ion.
The electron affinity of an atom in a neutral state is the energy gained when the atom gains a single electron, resulting in a negatively charged ion.
The ionization energy of an atom in a gas phase is higher than its electron affinity because the atoms are further apart and have a greater distance to be ionized.
Further considerations:
Ionisation energy and electron affinity are always positive values, as the energy is always required to remove or add an electron.
Ionisation energy and electron affinity are typically measured in units of energy (e.g., kJ, eV), depending on the specific atom or molecule being considered.
The ionization energy of an atom in a neutral state is usually higher than its electron affinity because it is easier to remove an electron from a neutral atom