Be
Beryllium
Element 4 · 9.0122 u
Beryllium is a lightweight, strong, and toxic alkaline earth metal.
Physical Properties
| Atomic Mass | 9.0122 u |
| Density | 1.85 g/cm³ |
| Melting Point | 1560.0 K |
| Boiling Point | 2742.0 K |
| Appearance | White-gray metallic |
| State at Room Temp | Solid |
Chemical Properties
| Electronegativity | 1.57 (Pauling) |
| 1st Ionization Energy | 899.5 kJ/mol |
| Electron Affinity | -48.0 kJ/mol |
| Oxidation States | +1, +2 |
Atomic Properties
| Electron Configuration | [He] 2s2 |
| Atomic Radius | 112.0 pm |
| Covalent Radius | 96.0 pm |
| Van der Waals Radius | 153.0 pm |
Discovery
| Discovered By | Louis Nicolas Vauquelin |
| Discovery Year | 1798 |
| Location | Paris, France |
| Named After | Greek 'beryllos' meaning beryl mineral |
About Beryllium
Beryllium is a relatively rare element occurring as a product of the spallation of larger nuclei. It is a hard, steel-gray metal that is remarkably stiff and lightweight. Beryllium is transparent to X-rays and is used in X-ray windows. Its compounds are toxic and can cause berylliosis.
Uses & Applications
Aerospace materials, X-ray windows, nuclear reactors, springs, and non-sparking tools for use around flammable gases.
Fun Fact
Beryllium is transparent to X-rays, making it ideal for X-ray tube windows, and it was originally called 'glucinium' because its compounds taste sweet (though they are toxic).
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 7 | - | 53.22 days | No |
| 9 | 1.0% | - | Yes |
| 10 | - | 1.39 million years | No |
Electron Configuration
[He] 2s2