Element 57
Lanthanum
Lanthanides
Lanthanum (La) is in the f-block of the periodic table — group 3, period 6.
Lanthanum is a soft, ductile, silvery-white metallic chemical element with symbol La and atomic number 57.
Key data
- Atomic number
- 57
- Atomic mass
- 138.905 u
- Group / Period
- 3 / 6
- Block
- f-block
- Phase at STP
- Solid
- Density
- 6.162 g/cm³
- Melting point
- 919.9 °C
- Boiling point
- 3463.8 °C
- Electron configuration
- [Xe] 5d16s2
Periodic table block
Lanthanum is in the f-block (group 3, period 6). Elements land in the f-block when their highest-energy electrons fill an f subshell — these are the lanthanides and actinides shown beneath the main table.
New to this? Periodic table blocks explained: s, p, d, and f
Common uses
- •Camera lenses
- •Hybrid car batteries
- •Lighter flints
Discovery
Year: 1839
Discovered by: Carl Gustaf Mosander
Frequently asked questions
What is the atomic number of Lanthanum?
Lanthanum has atomic number 57. Its symbol is La and its atomic mass is 138.905 u.
What category of element is Lanthanum?
Lanthanum is classified as lanthanides. It sits in group 3, period 6 of the periodic table.
What block of the periodic table is Lanthanum in?
Lanthanum is in the f-block (group 3, period 6). Its highest-energy electrons occupy the f subshell — you can see this in its electron configuration, [Xe] 5d16s2.
What is Lanthanum used for?
Common uses of Lanthanum include: Camera lenses, Hybrid car batteries, Lighter flints.
When was Lanthanum discovered?
Lanthanum was discovered in 1839 by Carl Gustaf Mosander.
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