57 La 138.905
Lanthanum
lanthanide
Properties
- Atomic number
- 57
- Atomic mass
- 138.905 u
- Category
- lanthanide
- Group
- f-block
- Period
- 6
- Block
- f-block
- State (room temp)
- Solid
- Outer-shell electrons
- 2
- Electronegativity
- 1.1 (Pauling)
- Density
- 6.162 g/cm³
- Melting point
- 919.85 °C
- Boiling point
- 3463.85 °C
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 5d¹
Noble-gas shorthand: [Xe] 5d¹ 6s²
Electrons per shell: 2, 8, 18, 18, 9, 2 — that's 2 in the outermost shell.
About Lanthanum
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.
- Discovered by Carl Gustaf Mosander
- Appearance: silvery white
Position in the periodic table
Data compiled from Wikipedia, PubChem, and IUPAC. Source.