Using Equation 26-26, we can write Equation 26-25 for the quantized electron orbital energy in terms of the Rydberg energy \(E_0\):
Again, the integer \(n\) identifies the orbit, and the atomic number \(Z\) specifies a particular element. Setting \(Z\) equal to 1 and n equal to 1 therefore tells us that the energy of the ground state of hydrogen is \(-13.6\) eV. We can also conclude from Equation 26-27 together with the value of the Rydberg energy that, in general, the energy of electrons in orbit around an atomic nucleus is between about \(-10\) eV and, for the largest elements (for which \(Z\) is about 100), \(-10^5\) eV. The Bohr model sets the scale for atomic electron energies.