How to Calculate the Ionization Potential

Ionization potential refers to the energy needed to separate electrons from an atom.
••• polymer in tube image by laurent dambies from

Electrons orbit around the nuclei of atoms in orbitals. The lowest, "default" orbitals are called the ground state. When energy is added to the system, such as by running an electrical current through a lightbulb filament, electrons are "excited" to higher orbitals. The energy that would be required to excite an electron so much that it is completely removed from an atom is called either the "ionization potential" or "ionization energy," though the latter is the more up to date term. For individual atoms, it is measured in electron volts (eV). On a larger scale, it is measured in kilojoules per mole (kJ/mol).

Calculating Ionization Energy

    Look up the ionization energy per atom in the periodic table linked in the resources section. Click on the element in question and write down the value under "First ionization." It would be possible to calculate this value knowing only the number of protons in the atom in question and the distance to the first orbital, but any source which contains this information will also give the first ionization energy.

    Determine how many moles of the element are being ionized. If you only know the mass, you must look up the atomic mass, also on most periodic tables. Divide the mass being ionized, in grams, by the atomic mass number. If you have 24 grams of oxygen, for example, which has an atomic mass of 16, you have 1.5 moles.

    Multiply the ionization energy you looked up by 96.485. 1 eV/particle is equal to 96.485 kJ/mol. The result is the molar ionization energy in kilojoules per mole.

    Multiply the answer from step three, in kJ/mol, by the number of moles you determined in step two. The answer is the total ionization energy of your sample, in kJ.

    Things You'll Need

    • Periodic table of the elements
    • Calculator

Related Articles

How to Calculate the Ionization Energy of Atoms
How to Calculate the First Ionization Energy of the...
Can We See Light Emitted by Hydrogen Atoms When They...
How to Know If an Element Has a Positive or Negative...
Why Do Compounds of Metals & Nonmetals Consist of Ions?
What Is a Noble Gas Configuration?
How to Calculate the Normality of HCL
How to Calculate Mass in Grams of a Molecule
What Orbits the Center of an Atom?
How to Find an Oxidation Number
How to Convert Amu to Joule
How to Convert Grams to AMU
How to Determine the Highest Ionization Energy
How to Convert Photons to Joules
How to Convert Atoms to Grams With a Calculator
How to Find the Number of Atoms in an Element
How to Calculate Isotopes
How to Calculate the pH of Ammonia Water Using KB
How to Find the Lattice Energy of a Compound
How to Convert AMU to Mole