Cesium (Cs)

General Properties

Symbol Cs
Atomic Number 55
Atomic Weight 132.9054519
Group
1 (alkali metals or hydrogen family/lithium family)
IA (IUPAC), IA (CAS)
Solid, Conductor, Alkali Metal, Metal, Stable, Natural
Period 6
Block s

Physical Properties

Density 1.87 g/cm3
Atomic Volume 70.0 cm3/mole
Atomic Radius 2.67 angstroms
Covalent Radius 225 pm
Crust Abundance 0.00019%
Crystal Structure Cubic: Body centered
Color Silver

Energy

Electronegativity 0.8 (Pauling Scale)
Electron Affinity 45.5 kJ/mol
1st Ionization Energy 382 kJ/mol
2nd Ionization Energy 2234.3 kJ/mol
3rd Ionization Energy 3400 kJ/mol
Specific Heat Capacity 0.24 J g−1 K−1
Thermal Conductivity 35.9 W·m−1·K−1

Electrons & Oxidation

Oxidation States 1
Electrons Per Shell 2 8 18 18 8 1
Electron Configuration [Xe] 6s1
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 6s1
Orbital Diagram
1s
↿⇂
2s
↿⇂
2p
↿⇂
↿⇂
↿⇂
3s
↿⇂
3p
↿⇂
↿⇂
↿⇂
3d
↿⇂
↿⇂
↿⇂
↿⇂
↿⇂
4s
↿⇂
4p
↿⇂
↿⇂
↿⇂
4d
↿⇂
↿⇂
↿⇂
↿⇂
↿⇂
4f
 
 
 
 
 
 
 
5s
↿⇂
5p
↿⇂
↿⇂
↿⇂
5d
 
 
 
 
 
5f
 
 
 
 
 
 
 
6s
↿ 
6p
 
 
 
6d
 
 
 
 
 
6f
 
 
 
 
 
 
 

Nuclear

Radioactive No

Media

Planetary Bohr Model of Cesium (Cs)
Lewis Dot Diagram of Cesium (Cs)
Description
Very soft, light gray, ductile metal.
Uses
Used as a 'getter' to remove air traces in vacuum and cathode-ray tubes. Also used in producing photoelectric devices and atomic clocks. Since it ionizes readily, it is used as an ion rocket motor propellant.
Sources
Found in pollucite [(Cs4Al4Si9O26).H2O] and as trace in lepidolite.
Pronounciation (English)
SEE-zi-em

Translations

Afrikaans Sesium
Aragonese Zesio
العربية سيزيوم
Armãneashte Tseziumu
asturianu Cesiu
azərbaycan dili Sezium
български Цезий
বাংলা সিজিয়াম
brezhoneg Seziom
bosanski Cezij[um]
Byelorussian Цэзій
Cebuano Cesyo
čeština Cesium
Chuvash Цези
Cymraeg Cesi
dansk Cæsium, Cesium
Deutsch Zäsium
Ελληνικά Καισιο
English Cesium
esperanto Cezio
español Cesio
eesti Tseesium
euskara Zesioa
فارسی سزیم
suomi Cesium
føroyskt Cæsium
français Césium
furlan Cesi
West-Frysk Cesium
Gaeilge Caeisiam
Gàidhlig Caesiam
galego Cesio
ગુજરાતી સિઝિયમનો
Gaelg Kaishum
Hakka Chinese Set (銫)
עברית צזיום
हिन्दी सीज़ियम
hrvatski Cezij
magyar Cézium
հայերեն Ցեզիում
Indonesia Sesium
íslenska Sesín
italiano Cesio
日本語 セシウム
ქართული ცეზიუმი
کٲشُر Céz
қазақ тілі Цезий
한국어 세슘
Kurdish Sezyûm
Komi Цезий
kernewek Cesyum
кыргызча Цезий
Latin Caesium
Lëtzebuergesch Zäsium
Lombard Cési
lingála Kaesu
lietuvių Cezis
latviešu Cēzijs
Mari Цезий
Maori Cesium
македонски Цезиум
മലയാളം സീസിയം
монгол Цези
Мокшан Цези
Bahasa Melayu Sesium
Malti Siżjum, ²Ċesju
Nahuatl Cesio
Nederlands Cesium
norsk Cesium
Occitan Cesi
ирон Цезий
polski Cez
português Césio
Runasimi Sesyu
română Cesiu
русский Цезий
slovenčina Cézium
slovenščina Cezij
Samoan Fayastonoskotriki
Samogitian Cezis
shqip Cezium
српски Цезијум
Southern Sotho Sesiamo
svenska Cesium
Kiswahili Sizi
தமிழ் சீசியம்
Tajik Сезий
ไทย ซีเซียม
Türkçe Sezyum
ئۇيغۇرچە سېزىي
українська Цезій
o‘zbek Seziy
Tiếng Việt Xezi, Xêzi
Võro Tseesium
中文

History

Discovered In
1860
Discovered By
Gustav Kirchhoff, Robert Bunsen
Discovered At
Germany
Word Origin
From the Latin word "caesius" meaning "sky blue" or "heavenly blue"