Lanthanum

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

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

Lanthanum: frequently asked questions

What is Lanthanum?

Lanthanum (La) is the chemical element with atomic number 57. It is a metal: specifically a lanthanide.

What is the atomic number of Lanthanum?

Lanthanum's atomic number is 57, which means every Lanthanum atom has 57 protons in its nucleus.

What is the electron configuration of Lanthanum?

The electron configuration of Lanthanum is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 5d1 (noble-gas shorthand: [Xe] 5d1 6s2). Its electrons are arranged in shells of 2, 8, 18, 18, 9, 2, with 2 in the outermost shell.

Is Lanthanum a metal or a nonmetal?

Lanthanum is a metal: specifically a lanthanide.

What group and period is Lanthanum in?

Lanthanum sits in the f-block (the lanthanide row) of period 6 on the periodic table.

Is Lanthanum a solid, liquid, or gas?

At room temperature, Lanthanum is a solid.

Position in the periodic table

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