Enter the atomic number into the calculator to determine the Ionization Energy. 

Ionization Energy Formula

The following equation is used to calculate the Ionization Energy.

Ei = SQRT( Z) *13.6
  • Where EI is the Ionization Energy (eV)
  • Z is the atomic number (atomic number)

To calculate an ionization energy, take the square root of the atomic number, then multiply by 13.6

What are the units for Ionization Energy?

The most common units for Ionization Energy are eV (electron volts).

How to Calculate Ionization Energy?

Example Problem:

The following example problem outlines the steps and information needed to calculate the Ionization Energy.

First, determine the atomic number. In this example, the atomic number is determined to be 14 (atomic number).

Finally, calculate the Ionization Energy using the formula above: 

Ei = SQRT( Z) *13.6

Inserting the values from above and solving the equation with the imputed values gives: Ei = SQRT(14) *13.6 = 50.88 (eV)