4Be9.01218
Beryllium
Alkaline earth metalsBlock sPeriod 2Group 2solid at 20 °C
- Configuration :
- [He] 2s²
- Atomic mass :
- 9.0121831 u
- French :
- Béryllium
3D Bohr-model representation of the Beryllium atom (symbol Be, atomic number Z=4). Electron shell configuration: 2, 2 electrons.
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Bohr model · educational
Bohr model of beryllium
Beryllium (Be) has 4 electrons, spread over 2 shells. The diagram places them on circles around the nucleus, from the K shell — the closest — outward.
| Shell | Electrons |
|---|---|
| K (n = 1) | 2 |
| L (n = 2) | 2 |
The Bohr model is a teaching picture: electrons do not travel in circular orbits, but the number of electrons per shell is exact.
Electron configuration
Full1s² 2s²
Short[He] 2s²
Valence electrons2
KLMNOPQ shells
K2
L2
Electronegativity
Pauling1.57
Allen1.576
Mulliken (eV)—
Atomic radii
Empirical105 pm
Calculated112 pm
Covalent96 pm
Van der Waals153 pm
Ionic radii (Shannon-Prewitt)
+245 pm
Successive ionisation energies
I₁899.5 kJ/mol
I₂1757.1 kJ/mol
I₃14848.7 kJ/mol
I₄21006.6 kJ/mol
Electron affinity—
Oxidation states
+1+2
Bold states = most common.
Warm-up
Beryllium — do you remember?
3 questions on this page. The right answer shows every time, and nothing is asked of you to play.
No account · one minute