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Information valid for Th-232 unless otherwise noted

Basic Information

Symbol: Th
Atomic Number: 90
Mass: 232.0381
Melting Point: 1750.0 C
Boiling Point: 4790.0 C
Number of Protons/Electrons: 90
Number of Neutrons: 142
Classification: Rare Earth
Crystal Structure: Cubic
Density @ 293 K: 11.72 g/cm3
Color: silvery

Atomic Structure

[Bohr Model of Thorium]
Number of Energy Levels: 7

  1. First Energy Level: 2
    Second Energy Level: 8
    Third Energy Level: 18
    Fourth Energy Level: 32
    Fifth Energy Level: 18
    Sixth Energy Level: 10
    Seventh Energy Level: 2


Isotope Half Life
Th-226 30.6 minutes
Th-227 18.72 days
Th-228 1.91 years
Th-229 7340.0 years
Th-230 75400.0 years
Th-231 1.06 days
Th-232 1.4E10 years
Th-233 22.3 minutes
Th-234 24.1 days


Date of Discovery: 1828
Discoverer: Jons Berzelius
Name Origin: Thor (Scandinavian god)
Uses: strong alloys, ultraviolet photoelectric cells
Obtained From: monazite, thorite

Related Links

Note: The external links below are not a part of this site and their content is not the responsibility of this site

  1. Cafe Thorium