12 - Magnesium alkaline earth metal
Discovered by Joseph Black in 1755
Magnesium is a chemical element with symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (Group 2, or alkaline earth metals) of the periodic table:they each have the same electron configuration in their outer electron shell producing a similar crystal structure. Magnesium is the ninth most abundant element in the universe.
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 | 2 | 2 in 3s |
24.3 u Atomic Mass
1.7 Å Atomic Radius
1.36k K Boiling Point
1.41 Å Covalent Radius
1.74 g/cm³ Density
−40 Electron Affinity
1.31 Electronegativity
7.65 eV First Ionization Energy
923 K Melting Point
3 Number of Shells
2 Electron Valency
12 Atomic Number
2, 8, 2 Electron Shell Occupations
1.02 J/(g K) Specific Heat