5
B
10.806
Boron
Metalloid
Group 13
Period 2
Block p
Boron is a chemical element of the periodic table with chemical symbol B and atomic number 5 with an atomic weight of 10.806 u and is classed as metalloid and is part of group 13 (boron group). Boron is solid at room temperature.
Boron in the periodic table
| Symbol | B |
| Atomic number | 5 |
| Group | 13 (Boron group) |
| Period | 2 |
| Block | p |
| Classification | Metalloid |
| Appearance | Black-brown |
| Color | Black |
| Number of protons | 5 p+ |
| Number of neutrons | 6 n0 |
| Number of electrons | 5 e- |
From Wikipedia, the free encyclopediaBoron is a metalloid chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in both the Solar system and the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals.
Physical properties
| Phase at STP | Solid |
| Density | 2.08 g/cm3 |
| Atomic weight | 10.806 u |
Thermal properties
| Melting point | 2349 K 2075.85 °C 3768.53 °F |
| Boiling point | 4200 K 3926.85 °C 7100.33 °F |
| Heat of vaporization | 507.8 kJ/mol |
Atomic properties
| Electronegativity (Pauling Scale) | 2.04 |
| Electron affinity | 26.989 kJ/mol |
| Oxidation states | −5, −1, 0, +1, +2, +3 (a mildly acidic oxide) |
| Ionization energies |
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Electron configuration for boron
Electron configuration Shorthand configuration | [He] 2s2 2p1 | ||||||||
| Full configuration | 1s2 2s2 2p1 | ||||||||
Electron configuration chart |
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| Electrons per shell | 2, 3 | ||||||||
| Valence electrons | 3 | ||||||||
| Valency electrons | 3 | ||||||||
| Bohr model | Figure: Shell diagram of Boron (B) atom. | ||||||||
Orbital Diagram |
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The history of Boron
| Discovery | Joseph Louis Gay-Lussac, Louis Jacques Thénard (1808) |
| First isolation | Humphry Davy (1808) |
Discovery of boron Boron was not recognized as an element until it was isolated by Sir Humphry Davy and by Joseph Louis Gay-Lussac and Louis Jacques Thénard. In 1808 Davy observed that electric current sent through a solution of borates produced a brown precipitate on one of the electrodes. In his subsequent experiments, he used potassium to reduce boric acid instead of electrolysis. He produced enough boron to confirm a new element and named it boracium. Gay-Lussac and Thénard used iron to reduce boric acid at high temperatures. By oxidizing boron with air, they showed that boric acid is its oxidation product. Jöns Jacob Berzelius identified it as an element in 1824. | |
| Original word | buraq / borax |
| Language of origin | Arabic |
| Name source | Mineral |
| Meaning | “Borax mineral” |
Naming The name is derived from the Arabic word 'buraq', a term signifying the element. | |