Symbol | Be |
Atomic number | 4 |
Group | 2 (Alkaline earth metal) |
Period | 2 |
Block | s |
Classification | Alkaline Earth Metal |
Appearance | White-gray metallic |
Color | SlateGray |
Number of protons | 4 p+ |
Number of neutrons | 5 n0 |
Number of electrons | 4 e- |
Phase at STP | Solid |
Density | 1.85 g/cm3 |
Atomic weight | 9.01218 u |
Melting point | 1560 K 1286.85 °C 2348.33 °F |
Boiling point | 2742 K 2468.85 °C 4475.93 °F |
Heat of vaporization | 297 kJ/mol |
Electronegativity (Pauling Scale) | 1.57 |
Electron affinity | -48 kJ/mol |
Oxidation states | 0, +1, +2 (an amphoteric oxide) |
Ionization energies |
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Discovery | Louis Nicolas Vauquelin (1798) |
First isolation | Friedrich Wöhler, Antoine Bussy (1828) |
Discovery of beryllium The mineral beryl, which contains beryllium, has been used at least since the Ptolemaic dynasty of Egypt. In the first century CE, Roman naturalist Pliny the Elder mentioned in his encyclopedia Natural History that beryl and emerald ("smaragdus") were similar. The Papyrus Graecus Holmiensis, written in the third or fourth century CE, contains notes on how to prepare artificial emerald and beryl. In a 1798 paper read before the Institut de France, Vauquelin reported that he found a new "earth" by dissolving aluminium hydroxide from emerald and beryl in an additional alkali. The editors of the journal Annales de Chimie et de Physique named the new earth "glucine" for the sweet taste of some of its compounds. Klaproth preferred the name "beryllina" due to the fact that yttria also formed sweet salts. The name "beryllium" was first used by Wöhler in 1828. |