57La138.9055
Lanthanum
Lanthanide
Solid at STP
Period 6Block FDiscovered 1839
[Xe]6s2 5d1
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.
📖 Read more on Wikipedia →Atomic Properties
| Atomic Number | 57 |
| Atomic Mass | 138.9055 u |
| Electron Configuration | [Xe]6s2 5d1 |
| Oxidation States | +3 |
| Electronegativity | 1.1 (Pauling) |
| Atomic Radius | 240 pm |
| Ionization Energy | 5.577 eV |
| Electron Affinity | 0.5 eV |
| Block | F |
Physical Properties
| Appearance | silvery white |
| Standard State | Solid |
| Melting Point | 1191 K (917.9 °C) |
| Boiling Point | 3737 K (3463.8 °C) |
| Density | 6.15 g/cm³ |
| Molar Heat | 27.11 J/(mol·K) |
| CPK Color | #70D4FF |
Classification
| Category | Lanthanide |
| Group Block | Lanthanide |
| Period | 6 |
| Block | F |
Discovery
| Year Discovered | 1839 |
| Discovered By | Carl Gustaf Mosander |
| Electron Shells | 2, 8, 18, 18, 9, 2 |