![[ATOM]](atom.gif) |
Cesium
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Information valid for Cs-133 unless otherwise noted
Basic Information
Symbol: Cs
Atomic Number: 55
Mass: 132.90546
Melting Point: 28.5 C
Boiling Point: 678.4 C
Number of Protons/Electrons: 55
Number of Neutrons: 78
Classification: Alkali Metal
Crystal Structure: Cubic
Density @ 293 K: 1.873 g/cm3
Color: silver
British Spelling: Caesium
IUPAC Spelling: Caesium
Atomic Structure
![[Bohr Model of Cesium]](b0055.gif) |
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Number of Energy Levels: 6
First Energy Level: 2
Second Energy Level: 8
Third Energy Level: 18
Fourth Energy Level: 18
Fifth Energy Level: 8
Sixth Energy Level: 1
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Isotopes
| Isotope |
Half Life |
| Cs-126 |
1.6 minutes |
| Cs-129 |
1.3 days |
| Cs-131 |
9.7 days |
| Cs-132 |
6.4 days |
| Cs-133 |
Stable |
| Cs-134 |
2.1 years |
| Cs-134m |
2.9 hours |
| Cs-135 |
2300000.0 years |
| Cs-136 |
13.2 days |
| Cs-137 |
30.2 years |
| Cs-138 |
32.2 minutes |
| Cs-139 |
9.3 minutes |
Facts
Date of Discovery: 1860
Discoverer: Fustov Kirchoff
Name Origin: From the Latin word caesius (sky blue)
Uses: removes air traces in vacuum tubes
Obtained From: pollucite, lepidolite