Periodic table / Lanthanum

Overview

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.

Electron configuration

The electron configuration of Lanthanum is [Xe] 5d16s2, with electron shells of 2, 8, 18, 18, 9, 2.

Physical and chemical properties

Lanthanum is classified as a lanthanide. It has an atomic mass of 138.905 and exists as a solid at standard conditions, appearing as silvery white.

Real-world uses of Lanthanum

Lanthanum, a lanthanide, is used in magnets, electronics, lighting, and other specialized high-tech applications.

Interesting facts about Lanthanum

• Lanthanum has the atomic number 57 and chemical symbol La.
• It belongs to period 6, group 3 of the periodic table.
• Lanthanum was discovered by Carl Gustaf Mosander.

Explore Lanthanum interactively

Want to compare Lanthanum with other elements or see it highlighted on the full table? Open the interactive periodic table and click on La to explore properties, trends, and neighboring elements. You can also test your knowledge with our periodic table quiz game.