57 - Lanthanum lanthanide
Discovered by Carl Gustaf Mosander in 1839
Lanthanum is a soft, ductile, silvery-white metallic chemical element with symbol La and atomic number 57. It tarnishes rapidly when exposed to air and is soft enough to be cut with a knife. It gave its name to the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table:it is also sometimes considered the first element of the 6th-period transition metals.
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 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
| 4 | 18 | 2 in 4s + 6 in 4p + 10 in 4d |
| 5 | 9 | 2 in 5s + 6 in 5p + 1 in 5d |
| 6 | 2 | 2 in 6s |
139 u Atomic Mass
2.7 Å Atomic Radius
3.74k K Boiling Point
2.07 Å Covalent Radius
6.16 g/cm³ Density
53 Electron Affinity
1.1 Electronegativity
5.58 eV First Ionization Energy
1.19k K Melting Point
6 Number of Shells
57 Atomic Number
2, 8, 18, 18, 9, 2 Electron Shell Occupations