8 - Oxygen diatomic nonmetal
Discovered by Carl Scheele in 1774
Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms compounds (notably oxides) with most elements. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium.
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 | 6 | 2 in 2s + 4 in 2p |
16 u Atomic Mass
0.65 Å Atomic Radius
90.2 K Boiling Point
0.66 Å Covalent Radius
0.00143 g/cm³ Density
141 Electron Affinity
3.44 Electronegativity
13.6 eV First Ionization Energy
50.5 K Melting Point
2 Number of Shells
6 Electron Valency
8 Atomic Number
2, 6 Electron Shell Occupations
0.918 J/(g K) Specific Heat