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Caesium Element in Periodic Table | Atomic Number Atomic Mass


Caesium Element:

Caesium is an element in the Group I and 6th period of periodic table. Its atomic number is 55 and has a single electron in its outermost s-orbital. Like all the metals in the first group of periodic table, caesium too has exhibits preparedness to lose one electron while forming compounds with other elements which are short by one electron to attain stable electronic configuration resembling inert gases. Hence, the combining capacity or valency of Cs is 1. With its melting point at 28.5°C, Cs is liquid at or slightly above room temperature.  Being one of the most reactive metals, Cs reacts with water even at ­-116°C. Mercury is the only metal whose melting point is at 38.83°C lower than caesium. Hence Cs caches fire immediately when exposed to air and pyrophoric. Out of 39 known isotopes of  CS, the most stable isotope is 133Cs with 78 neutrons.

Caesium Element Uses:

The non-radioactive Cs is used in oil-drilling industry. Due to its hyperfine structure of caesium- 133 atoms, it is used making of high precision atomic clocks. Caesium vapor is used in most of the common magnetometers. Caesium reacts with halogens to form respective halides and the crystals of caesium iodide, caesium bromide and caesium fluoride in scintillation counters widely used in mineral exploration and in detecting gamma and x-ray radiation in particle physics. It is also used in high energy lasers.


Caesium Element Information:

Discovery year:1860

Discovered by:Robert Bunsen and Gustav Kirchhoff

Atomic number: 55

Relative atomic mass: 132.905 

Electron configuration: [Xe] 6s1

Block: s-block

Other elements in the same block:

Hydrogen, Helium, Lithium, Beryllium, Sodium, Magnesium, Potassium, Calcium, Rubidium, Strontium, Barium, francium and Radium are other elements in the s-block.

Period: period 6

Other elements in the same period:

Barium, LanthanumCerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, Hafnium, Tantalum, Tungsten, Rhenium, Osmium, Iridium, Platinum, Gold, Mercury, Thallium, Lead, Bismuth, Polonium, Astatine and Radon are the elements in the same period.

Group: group 1 (alkali metals)

Other elements in the same group:

Hydrogen, Lithium, Sodium, Potassium, Rubidium  and   francium are the elements in the same group.

Other elements in the same orbital:

Barium is the element in the same orbital.

Allotropes: none

Key isotopes: 133Cs 

Melting point: 28.5°C, 83.3°F, 301.7 K 

Boiling point: 671°C, 1240°F, 944 K

Element category:  alkali metal

Density (g cm−3): 1.873

CAS number: 7440-46-2

Color: pale gold

You can know detailed information for each element,

Hydrogen, HeliumLithiumBerylliumBoronCarbonNitrogenOxygenFluorine,  Neon , SodiumMagnesiumAluminiumSiliconPhosphorusSulfurChlorineArgon, PotassiumCalciumScandiumTitaniumVanadiumChromiumManganeseIronCobaltNickelCopperZincGalliumGermaniumArsenicSeleniumBromine, Krypton,  Rubidium, StrontiumYttriumZirconiumNiobiumMolybdenumTechnetiumRutheniumRhodiumPalladiumSilverCadmiumIndiumTinAntimonyTelluriumIodine, Xenon,  Caesium, BariumLanthanum,  CeriumPraseodymiumNeodymiumPromethiumSamariumEuropiumGadoliniumTerbiumDysprosiumHolmiumErbiumThuliumYtterbiumLutetiumHafniumTantalumTungstenRheniumOsmiumIridiumPlatinumGoldMercuryThalliumLeadBismuthPoloniumAstatine, Radon,  Francium, RadiumActiniumThoriumProtactiniumUraniumNeptuniumPlutoniumAmericiumCuriumBerkeliumCaliforniumEinsteiniumFermiumMendeleviumNobeliumLawrenciumRutherfordiumDubniumSeaborgiumBohriumHassiumMeitneriumDarmstadtiumRoentgeniumCoperniciumNihoniumFleroviumMoscoviumLivermoriumTennessine, Oganesson.

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