Chemical Elements.com - Actinium (Ac)

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Basic Information

Name: Actinium
Symbol: Ac
Atomic Number: 89
Atomic Mass: (227.0) amu
Melting Point: 1050.0 °C (1323.15 K, 1922.0 °F)
Boiling Point: 3200.0 °C (3473.15 K, 5792.0 °F)
Number of Protons/Electrons: 89
Number of Neutrons: 138
Classification: Rare Earth
Crystal Structure: Cubic
Density @ 293 K: 10.07 g/cm³
Color: Silvery

Atomic Structure

Number of Energy Levels: 7

First Energy Level:

Second Energy Level:

Third Energy Level:

Fourth Energy Level:

Fifth Energy Level:

Sixth Energy Level:

Seventh Energy Level:

Isotopes

Isotope	Half Life
Ac-225	10.0 days
Ac-226	1.2 days
Ac-227	21.8 years
Ac-228	6.16 hours

Facts

Date of Discovery: 1899
Discoverer: Andre Debierne
Name Origin: From the Greek word aktinos (ray)
Uses: No uses known
Obtained From: extremely rare

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