Modern Physics

Hydrogen-like Atom Energy

En=−13.6 eV×Z2n2E_n = -13.6\text{ eV} \times \frac{Z^2}{n^2}

Generalized Bohr energy formula for hydrogen-like atoms (single electron). Energy scales with Z² making inner electrons in heavy atoms much more tightly bound.

Variables

En
Energy of level n
eV
Z
Atomic number (nuclear charge)
Allowed values: greater than 0, whole number
unitless
n
Principal quantum number
Allowed values: greater than 0, whole number
unitless

Derivation

Extended from Bohr model by accounting for nuclear charge Z in the Coulomb potential.

Your notes

0/5000

Check value

Round inputs run through this page's calculator. Use it to test your own working or a rearranged form. It is a test case, not a real-world example.

  • Z = 2 (Atomic number (nuclear charge))
  • n = 3 (Principal quantum number)

Result: En = -6.0444444 eV

Where this formula is listed

Common questions

What is the Hydrogen-like Atom Energy formula?

Hydrogen-like Atom Energy is written E_n = −13.6 eV × Z²/n². Generalized Bohr energy formula for hydrogen-like atoms (single electron). Energy scales with Z² making inner electrons in heavy atoms much more tightly bound. It belongs to Modern Physics, under Atomic Physics.

What are the units in E_n = −13.6 eV × Z²/n²?

In SI units, E_n is energy of level n, measured in eV; Z is atomic number (nuclear charge) (dimensionless); n is principal quantum number (dimensionless).

How is the Hydrogen-like Atom Energy formula derived?

Extended from Bohr model by accounting for nuclear charge Z in the Coulomb potential. The result is E_n = −13.6 eV × Z²/n².