Electron Configuration Builder
Pick an element and see its levels, sublevels, configuration and valence electrons.
Pick an element (Z = 1 to 20)
Each step changes Z and the electron count together, so the atom stays neutral.
Bohr diagram
Orange dots are valence electrons (outer level). Blue dots are inner electrons.
Your atom
Lithium (Li)
| Atomic number (Z) | |
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| Electron arrangement | |
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| Electron configuration | |
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| Noble-gas shorthand | |
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| Valence electrons | |
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| Last electron goes in | |
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Orbital boxes
Each box holds 2 electrons. In p boxes, put one arrow in each box before pairing (Hund's rule).
Levels hold 2, 8, 8, then level 4 starts with the next 2 (K and Ca). Fill order: 1s 2s 2p 3s 3p 4s. Elements 1 to 20 only.