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57 La
Element Revision Sheet

Lanthanum (La)

Lanthanoids Block D Group Lanthanides • Period 6
Superhero Identity

"The Hidden Lens, a hero who was hard to find but now makes vision clearer in high-tech cameras."

A memorable persona to anchor La in your mind.

Density

6.162

Grams per cm³

Melting Point

920

Celsius (°C)

Atomic Radius

240

Radius (pm)

Everyday Connection

Daily Life Link

Lanthanum is found in a high-quality camera lens.

Discovery & History

Year Discovered

1839

Discovered By

Carl Gustaf Mosander

Origin of Name

"The name is derived from the Greek 'lanthanein', meaning to lie hidden."

Technical Properties

Atomic Mass

138.905 u

Standard State

solid

Boiling Point

3464°C

Electron Configuration

[Xe] 5d16s2

1st Ionization Energy

5.577 eV

Electron Affinity

N/A

Oxidation States

[+3]
Appearance

"Lanthanum is a soft, silvery-white, ductile metal."

Did You Know?

1

It is the first element of the lanthanide series, a group of 15 chemically similar elements.

2

Adding lanthanum oxide to glass increases its refractive index and clarity with low dispersion, making it perfect for high-end camera and telescope lenses.

3

The metal is so soft it can be cut with a knife.

4

Mischmetal, a material used to make the flints in lighters, is about 25% lanthanum.

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