Beryllium is a chemical element wi seembol Be an atomic nummer 4. It is creaut throu stellar nucleosynthesis an is a relatively rare element in the universe . It is a divalent element that occurs naiturally anerly in combination wi ither elements an minerals. Notable gemstanes whilk contain beryllium include beryl (aquamarine , emerald ) an chrysoberyl . As a free element , it is a steel-gray, strang, lichtwicht an brickle alkaline yird metal .
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Beryllium, 4 Be Beryllium Pronunciation (bə-RIL -ee-əm ) Appearance white-gray metallic Standard atomic weight A r, std (Be)7000901218310000000♠ 9.0121831 (5)[1] Beryllium in the periodic cairt
Atomic nummer (Z ) 4 Group group 2 (alkaline yird metals) Period period 2 Block s-block Element category Alkaline yird metal Electron confeeguration [ He ] 2s2 Electrons per shell 2, 2 Pheesical properties Phase at STP solit Meltin pynt 1560 K (1287 °C, 2349 °F) Bylin pynt 3243 K (2970 °C, 5378 °F) Density (near r.t. ) 1.85 g/cm3 when liquid (at m.p. ) 1.690 g/cm3 Creetical pynt 5205 K, MPa (extrapolatit) Heat o fusion 12.2 kJ/mol Heat o vapourisation 292 kJ/mol Molar heat capacity 16.443 J/(mol·K) Vapour pressur
P (Pa)
1
10
100
1 k
10 k
100 k
at T (K)
1462
1608
1791
2023
2327
2742
Atomic properties Oxidation states 0,[2] +1,[3] +2 (an amphoteric oxide) Electronegativity Pauling scale: 1.57 Ionisation energies 1st: 899.5 kJ/mol 2nd: 1757.1 kJ/mol 3rd: 14848.7 kJ/mol (more ) Atomic radius empirical: 112 pm Covalent radius 96±3 pm Van der Waals radius 153 pm Colour lines in a spectral range Spectral lines o berylliumIther properties Naitural occurrence primordial Creestal structur hexagonal close-packed (hcp)Speed o soond thin rod 12890 m/s (at r.t. )[4] Thermal expansion 11.3 µm/(m·K) (at 25 °C) Thermal conductivity 200 W/(m·K) Electrical resistivity 36 nΩ·m (at 20 °C) Magnetic orderin diamagnetic Young's modulus 287 GPa Shear modulus 132 GPa Bulk modulus 130 GPa Poisson ratio 0.032 Mohs haurdness 5.5 Vickers haurdness 1670 MPa Brinell haurdness 590–1320 MPa CAS Nummer 7440-41-7 History Diskivery Louis Nicolas Vauquelin (1797)First isolation Friedrich Wöhler & Antoine Bussy (1828)Main isotopes o beryllium
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