First ionization energy of the elements, hydrogen to krypton
Helium holds its electrons tightest, at 24.6 eV. Every peak is a noble gas and every plunge right after it an alkali metal: the rhythm of the periodic table.
What does this axis measure?
Ionization energy (eV)
What does this axis measure?
Atomic number (protons)
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- y ↑
- Ionization energy (eV)
- x →
- Atomic number (protons)
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The data: 36 points
| Atomic number (protons) | Ionization energy (eV) |
|---|---|
| 1 | 13.598 |
| 2 | 24.587 |
| 3 | 5.392 |
| 4 | 9.323 |
| 5 | 8.298 |
| 6 | 11.26 |
| 7 | 14.534 |
| 8 | 13.618 |
| 9 | 17.423 |
| 10 | 21.565 |
| 11 | 5.139 |
| 12 | 7.646 |
| 13 | 5.986 |
| 14 | 8.152 |
| 15 | 10.487 |
| 16 | 10.36 |
| 17 | 12.968 |
| 18 | 15.76 |
| 19 | 4.341 |
| 20 | 6.113 |
| 21 | 6.561 |
| 22 | 6.828 |
| 23 | 6.746 |
| 24 | 6.767 |
| 25 | 7.434 |
| 26 | 7.902 |
| 27 | 7.881 |
| 28 | 7.64 |
| 29 | 7.726 |
| 30 | 9.394 |
| 31 | 5.999 |
| 32 | 7.9 |
| 33 | 9.815 |
| 34 | 9.752 |
| 35 | 11.814 |
| 36 | 14 |
- Ran in puzzle #4 on September 30, 2026. Play it
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