Boron (B)

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.

Beryllium Periodic table Carbon

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	800.6 kJ/mol 2427.1 kJ/mol 3659.7 kJ/mol 25025.8 kJ/mol 32826.7 kJ/mol

Electron configuration for boron

Electron configuration

Shorthand configuration

[He] 2s² 2p¹

Electron configuration

Full configuration

1s² 2s² 2p¹

Electron configuration chart

1s²
2s²	2p¹

Electrons per shell

2, 3

Valence electrons

3

Valency electrons

3

Bohr model

Figure: Shell diagram of Boron (B) atom.

Orbital Diagram

1s
2s		2p

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.

Periodic table history

Identifiers

List of unique identifiers for Boron in various chemical registry databases

CAS Number	7440-42-8
ChemSpider ID	4575371
EC number	231-151-2
PubChem CID Number	5462311