27 - Cobalt transition metal
Discovered by Georg Brandt in 1735
Cobalt is a chemical element with symbol Co and atomic number 27. Like nickel, cobalt in the Earth's crust is found only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
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 | 8 | 2 in 2s + 6 in 2p |
| 3 | 15 | 2 in 3s + 6 in 3p + 7 in 3d |
| 4 | 2 | 2 in 4s |
58.9 u Atomic Mass
1.7 Å Atomic Radius
3.2k K Boiling Point
1.26 Å Covalent Radius
8.9 g/cm³ Density
63.9 Electron Affinity
1.88 Electronegativity
7.88 eV First Ionization Energy
1.77k K Melting Point
4 Number of Shells
27 Atomic Number
2, 8, 15, 2 Electron Shell Occupations