5 - Boron metalloid
Discovered by Joseph Gay-Lussac in 1808
Boron 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.
H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
57-71 La-Lu Lanthanides
89-103 Ac-Lr Actinides
| Shell | Electrons | Orbitals |
|---|---|---|
| 1 | 2 | 2 in 1s |
| 2 | 3 | 2 in 2s + 1 in 2p |
10.8 u Atomic Mass
1.2 Å Atomic Radius
4.2k K Boiling Point
0.84 Å Covalent Radius
2.08 g/cm³ Density
27 Electron Affinity
2.04 Electronegativity
8.3 eV First Ionization Energy
2.57k K Melting Point
2 Number of Shells
3 Electron Valency
5 Atomic Number
2, 3 Electron Shell Occupations
1.03 J/(g K) Specific Heat