Periodic Table Element Comparison: Compare Elements - Rubidium vs Cesium
Compare Rubidium and Cesium on the basis of their properties, attributes and periodic table facts. Compare elements on more than 90 properties. All the elements of similar categories show a lot of similarities and differences in their chemical, atomic, physical properties and uses. These similarities and dissimilarities should be known while we study periodic table elements. You can study the detailed comparison between Rubidium vs Cesium with most reliable information about their properties, attributes, facts, uses etc. You can compare Rb vs Cs on more than 90 properties like electronegativity , oxidation state, atomic shells, orbital structure, Electronaffinity, physical states, electrical conductivity and many more. Rubidium and Cesium comparison table on more than 90 properties.
Rubidium and Cesium Comparison
Facts
| Name | Rubidium | Cesium |
|---|---|---|
| Atomic Number | 37 | 55 |
| Atomic Symbol | Rb | Cs |
| Atomic Weight | 85.4678 | 132.90545 |
| Phase at STP | Solid | Solid |
| Color | Silver | Silver |
| Metallic Classification | Alkali Metal | Alkali Metal |
| Group in Periodic Table | group 1 | group 1 |
| Group Name | lithium family | lithium family |
| Period in Periodic Table | period 5 | period 6 |
| Block in Periodic Table | s -block | s -block |
| Electronic Configuration | [Kr] 5s1 | [Xe] 6s1 |
| Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 8, 1 | 2, 8, 18, 18, 8, 1 |
| Melting Point | 312.46 K | 301.59 K |
| Boiling Point | 961 K | 944 K |
| CAS Number | CAS7440-17-7 | CAS7440-46-2 |
| Neighborhood Elements | Neighborhood Elements of Rubidium | Neighborhood Elements of Cesium |
History
| Parameter | Rubidium | Cesium |
|---|---|---|
| History | The element Rubidium was discovered by R. Bunsen and G. R. Kirchhoff in year 1861 in Germany. Rubidium derived its name from the Latin rubidus, meaning 'deep red'. | The element Cesium was discovered by R. Bunsen and R. Kirchhoff in year 1860 in Germany. Cesium derived its name from the Latin caesius, meaning 'sky blue'. |
| Discovery | R. Bunsen and G. R. Kirchhoff (1861) | R. Bunsen and R. Kirchhoff (1860) |
| Isolated | Hevesy () | C. Setterberg (1882) |
Presence: Abundance in Nature and Around Us
Parts per billion (ppb) by weight / by atoms (1ppb =10^-7 %)
| Property | Rubidium | Cesium |
|---|---|---|
| Abundance in Universe | 10 / 0.1 | 0.8 / 0.01 |
| Abundance in Sun | 30 / 0.4 | 8 / 0.07 |
| Abundance in Meteorites | 3300 / 770 | 140 / 20 |
| Abundance in Earth's Crust | 60000 / 14000 | 1900 / 290 |
| Abundance in Oceans | 120 / 8.7 | 0.5 / 0.023 |
| Abundance in Humans | 4600 / 340 | 20 / 1 |
Crystal Structure and Atomic Structure
| Property | Rubidium | Cesium |
|---|---|---|
| Atomic Volume | 55.788 cm3/mol | 70.732 cm3/mol |
| Atomic Radius | 265 pm | 298 pm |
| Covalent Radius | 211 pm | 225 pm |
| Van der Waals Radius | 303 pm | 343 pm |
Atomic Spectrum - Spectral Lines | ||
| Emission Spectrum |  |  |
| Absorption Spectrum |  | Not available |
| Lattice Constant | 558.5, 558.5, 558.5 pm | 614.1, 614.1, 614.1 pm |
| Lattice Angle | π/2, π/2, π/2 | π/2, π/2, π/2 |
| Space Group Name | Im_ 3m | Im_ 3m |
| Space Group Number | 229 | 229 |
| Crystal Structure | Body Centered Cubic  | Body Centered Cubic |
Atomic and Orbital Properties
| Property | Rubidium | Cesium |
|---|---|---|
| Atomic Number | 37 | 55 |
| Number of Electrons (with no charge) | 37 | 55 |
| Number of Protons | 37 | 55 |
| Mass Number | 85.4678 | 132.90545 |
| Number of Neutrons | 48 | 78 |
| Shell structure (Electrons per energy level) | 2, 8, 18, 8, 1 | 2, 8, 18, 18, 8, 1 |
| Electron Configuration | [Kr] 5s1 | [Xe] 6s1 |
| Valence Electrons | 5s1 | 6s1 |
| Oxidation State | 1 | 1 |
| Atomic Term Symbol (Quantum Numbers) | 2S1/2 | 2S1/2 |
| Shell structure |  |  |
Isotopes and Nuclear Properties
Rubidium has 1 stable naturally occuring isotopes while Cesium has 1 stable naturally occuring isotopes.
| Parameter | Rubidium | Cesium |
|---|---|---|
| Known Isotopes | 71Rb, 72Rb, 73Rb, 74Rb, 75Rb, 76Rb, 77Rb, 78Rb, 79Rb, 80Rb, 81Rb, 82Rb, 83Rb, 84Rb, 85Rb, 86Rb, 87Rb, 88Rb, 89Rb, 90Rb, 91Rb, 92Rb, 93Rb, 94Rb, 95Rb, 96Rb, 97Rb, 98Rb, 99Rb, 100Rb, 101Rb, 102Rb | 112Cs, 113Cs, 114Cs, 115Cs, 116Cs, 117Cs, 118Cs, 119Cs, 120Cs, 121Cs, 122Cs, 123Cs, 124Cs, 125Cs, 126Cs, 127Cs, 128Cs, 129Cs, 130Cs, 131Cs, 132Cs, 133Cs, 134Cs, 135Cs, 136Cs, 137Cs, 138Cs, 139Cs, 140Cs, 141Cs, 142Cs, 143Cs, 144Cs, 145Cs, 146Cs, 147Cs, 148Cs, 149Cs, 150Cs, 151Cs |
| Stable Isotopes | Naturally occurring stable isotopes: 85Rb | Naturally occurring stable isotopes: 133Cs |
| Neutron Cross Section | 0.38 | 29 |
| Neutron Mass Absorption | 0.0003 | 0.0077 |
Chemical Properties: Ionization Energies and electron affinity
| Property | Rubidium | Cesium |
|---|---|---|
| Valence or Valency | 1 | 1 |
| Electronegativity | 0.82 Pauling Scale | 0.79 Pauling Scale |
| Electron Affinity | 46.9 kJ/mol | 45.5 kJ/mol |
| Ionization Energies | 1st: 403 kJ/mol 2nd: 2633 kJ/mol 3rd: 3860 kJ/mol 4th: 5080 kJ/mol 5th: 6850 kJ/mol 6th: 8140 kJ/mol 7th: 9570 kJ/mol 8th: 13120 kJ/mol 9th: 14500 kJ/mol 10th: 26740 kJ/mol | 1st: 375.7 kJ/mol 2nd: 2234.3 kJ/mol 3rd: 3400 kJ/mol |
Physical Properties
| Property | Rubidium | Cesium |
|---|---|---|
| Density | 1.532 g/cm3 | 1.879 g/cm3 |
| Molar Volume | 55.788 cm3/mol | 70.732 cm3/mol |
Elastic Properties | ||
| Young Modulus | 2.4 | 1.7 |
| Shear Modulus | - | - |
| Bulk Modulus | 2.5 GPa | 1.6 GPa |
| Poisson Ratio | - | - |
Hardness - Tests to Measure of Hardness of Element | ||
| Mohs Hardness | 0.3 MPa | 0.2 MPa |
| Vickers Hardness | - | - |
| Brinell Hardness | 0.216 MPa | 0.14 MPa |
Electrical Properties | ||
| Electrical Conductivity | 8300000 S/m | 5000000 S/m |
| Resistivity | 1.2e-7 m Ω | 2e-7 m Ω |
| Superconducting Point | - | - |
Heat and Conduction Properties | ||
| Thermal Conductivity | 58 W/(m K) | 36 W/(m K) |
| Thermal Expansion | - | - |
Magnetic Properties | ||
| Magnetic Type | Paramagnetic | Paramagnetic |
| Curie Point | - | - |
| Mass Magnetic Susceptibility | 2.6e-9 m3/kg | 2.8e-9 m3/kg |
| Molar Magnetic Susceptibility | 2.22e-10 m3/mol | 3.72e-10 m3/mol |
| Volume Magnetic Susceptibility | 0.00000398 | 0.00000526 |
Optical Properties | ||
| Refractive Index | - | - |
Acoustic Properties | ||
| Speed of Sound | 1300 m/s | - |
Thermal Properties - Enthalpies and thermodynamics
| Property | Rubidium | Cesium |
|---|---|---|
| Melting Point | 312.46 K | 301.59 K |
| Boiling Point | 961 K | 944 K |
| Critical Temperature | 2093 K | 1938 K |
| Superconducting Point | - | - |
Enthalpies | ||
| Heat of Fusion | 2.19 kJ/mol | 2.09 kJ/mol |
| Heat of Vaporization | 72 kJ/mol | 65 kJ/mol |
| Heat of Combustion | - | - |
Regulatory and Health - Health and Safety Parameters and Guidelines
| Parameter | Rubidium | Cesium |
|---|---|---|
| CAS Number | CAS7440-17-7 | CAS7440-46-2 |
| RTECS Number | RTECSVL8500000 | RTECSFK9225000 |
| DOT Hazard Class | 4.3 | 4.3 |
| DOT Numbers | 1423 | 1407 |
| EU Number | - | - |
| NFPA Fire Rating | 3 | - |
| NFPA Health Rating | 2 | - |
| NFPA Reactivity Rating | - | - |
| NFPA Hazards | Water Reactive | Water Reactive |
| AutoIgnition Point | - | - |
| Flashpoint | - | - |
Compare With Other Elements
Compare Rubidium and Cesium with other elements of the periodic table.