WebElements Periodic Table of the Elements | Caesium

Properties of caesium atoms

The electron affinity of caesium is 45.5 kJ mol^-1.

Ionisation Energies

This section includes ionisation energies of caesium.

Ionisation energy number	Enthalpy /kJ mol^-1
1st	375.7
2nd	2234.3
3rd	3400

Ionisation energies of Cs

Electronic configuration

The following represents the electronic configuration and its associated term symbol for the ground state neutral gaseous atom. The configuration associated with caesium in its compounds is not necessarily the same.

Ground state electron configuration: [Xe].6s¹
Shell structure: 2.8.18.18.8.1
Term symbol: ²S_1/2

Kossel shell structure of Cs
A schematic representation of the shell structure of caesium - not what the atom of caesium "looks like".

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	Rb	Sr
	Cs	Ba
	Fr	Ra

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Caesium	Césium
C�sium	Cesium
Cesio	Cesio
Cesium	Césio

Caesium
- Essential data: names, symbol, atomic number, and atomic weight; block, period, and group in periodic table; description; standard state; registry number; and isolation
- History: meaning of name; discovery; and history of the element
- Find a property
Caesium around us
- Uses
- Geology: Abundance of elements in the universe; the sun; meteorites; Earth's crust; oceans; and streams
- Biology: Abundance in humans; biological role; and health hazards)
Caesium compounds
- Compounds: halides, oxides, sulfides, hydrides, and complexes; lattice energies; and reduction potentials
- Electronegativities: Pauling; Sanderson; Allred Rochow; Mulliken-Jaffe; and Allen
- Bond enthalpies of diatomic species
- Lattice energies
Element properties
- Physics properties: Boiling point; melting point; density; molar volume; thermal conductivity; and electrical resistivity; bulk modulus; critical temperature; superconductivity temperature; hardness (mineralogical, Brinell, and Vickers); linear expansion coefficient; Poisson's ratio; reflectivity; refractive index; rigidity modulus; Young's modulus; velocity of sound
- Images
- Reactions of calcium: reactions of caesium with air; water; halogens; acids; and bases
- Crystal structure
- Thermochemistry: enthalpies of atomization, fusion, and vaporization; thermodynamic properties
Atom properties
- Electron shell properties: Electronic configuration; term symbol; electron affinity; ionization energies; and atomic spectra
- Atom sizes: atomic radius; Shannon and Pauling ionic radii; covalent radius; metallic radius; element bond length; and Van der Waals radius
- Atomic orbital properties: effective nuclear charge; electron binding energies; and valence orbital radii maxima
Nuclear properties
- Isotopes: isotope abundances; radioactive isotopes; isotope masses; nuclear spins; and nuclear magnetic moment
- NMR properties: frequencies; isotopes; magnetogyric ratios; quadrupole moments; receptivities; and relative sensitivities

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