The first dozen energy levels of selected neutral atoms (eV below ionization)

Source: NIST Atomic Spectra Database

level	element
	hydrogen	helium	neon	sodium
∞	0	0	0	0
…	…	…	…	…
12	−0.094	−0.914	−2.861	−0.794
11	−0.112	−0.993	−2.872	−0.795
10	−0.136	−1.500	−2.928	−0.851
9	−0.167	−1.513	−2.952	−0.855
8	−0.212	−1.580	−2.989	−0.856
7	−0.277	−1.667	−3.010	−1.023
6	−0.377	−1.869	−3.183	−1.386
5	−0.543	−3.369	−4.717	−1.522
4	−0.849	−3.623	−4.850	−1.948
3	−1.510	−3.971	−4.894	−3.035
2	−3.399	−4.767	−4.946	−3.037
1	−13.598	−24.587	−21.565	−5.139