Periodic Table Element Comparison: Compare Elements - Potassium vs Rubidium
Compare Potassium and Rubidium 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 Potassium vs Rubidium with most reliable information about their properties, attributes, facts, uses etc. You can compare K vs Rb on more than 90 properties like electronegativity , oxidation state, atomic shells, orbital structure, Electronaffinity, physical states, electrical conductivity and many more. Potassium and Rubidium comparison table on more than 90 properties.
Potassium and Rubidium Comparison
Facts
| Name | Potassium | Rubidium |
|---|---|---|
| Atomic Number | 19 | 37 |
| Atomic Symbol | K | Rb |
| Atomic Weight | 39.0983 | 85.4678 |
| 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 4 | period 5 |
| Block in Periodic Table | s -block | s -block |
| Electronic Configuration | [Ar] 4s1 | [Kr] 5s1 |
| Electronic Shell Structure (Electrons per shell) | 2, 8, 8, 1 | 2, 8, 18, 8, 1 |
| Melting Point | 336.53 K | 312.46 K |
| Boiling Point | 1032 K | 961 K |
| CAS Number | CAS7440-09-7 | CAS7440-17-7 |
| Neighborhood Elements | Neighborhood Elements of Potassium | Neighborhood Elements of Rubidium |
History
| Parameter | Potassium | Rubidium |
|---|---|---|
| History | The element Potassium was discovered by H. Davy in year 1807 in United Kingdom. Potassium derived its name from New Latin potassa, 'potash' (kalium in Latin). | 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'. |
| Discovery | H. Davy (1807) | R. Bunsen and G. R. Kirchhoff (1861) |
| Isolated | H. Davy (1807) | Hevesy () |
Presence: Abundance in Nature and Around Us
Parts per billion (ppb) by weight / by atoms (1ppb =10^-7 %)
| Property | Potassium | Rubidium |
|---|---|---|
| Abundance in Universe | 3000 / 100 | 10 / 0.1 |
| Abundance in Sun | 4000 / 100 | 30 / 0.4 |
| Abundance in Meteorites | 710000 / 370000 | 3300 / 770 |
| Abundance in Earth's Crust | 15000000 / 7800000 | 60000 / 14000 |
| Abundance in Oceans | 416000 / 65800 | 120 / 8.7 |
| Abundance in Humans | 2000000 / 320000 | 4600 / 340 |
Crystal Structure and Atomic Structure
| Property | Potassium | Rubidium |
|---|---|---|
| Atomic Volume | 45.68 cm3/mol | 55.788 cm3/mol |
| Atomic Radius | 243 pm | 265 pm |
| Covalent Radius | 196 pm | 211 pm |
| Van der Waals Radius | 275 pm | 303 pm |
Atomic Spectrum - Spectral Lines | ||
| Emission Spectrum |  |  |
| Absorption Spectrum |  |  |
| Lattice Constant | 532.8, 532.8, 532.8 pm | 558.5, 558.5, 558.5 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 | Potassium | Rubidium |
|---|---|---|
| Atomic Number | 19 | 37 |
| Number of Electrons (with no charge) | 19 | 37 |
| Number of Protons | 19 | 37 |
| Mass Number | 39.0983 | 85.4678 |
| Number of Neutrons | 20 | 48 |
| Shell structure (Electrons per energy level) | 2, 8, 8, 1 | 2, 8, 18, 8, 1 |
| Electron Configuration | [Ar] 4s1 | [Kr] 5s1 |
| Valence Electrons | 4s1 | 5s1 |
| Oxidation State | 1 | 1 |
| Atomic Term Symbol (Quantum Numbers) | 2S1/2 | 2S1/2 |
| Shell structure |  |  |
Isotopes and Nuclear Properties
Potassium has 2 stable naturally occuring isotopes while Rubidium has 1 stable naturally occuring isotopes.
| Parameter | Potassium | Rubidium |
|---|---|---|
| Known Isotopes | 32K, 33K, 34K, 35K, 36K, 37K, 38K, 39K, 40K, 41K, 42K, 43K, 44K, 45K, 46K, 47K, 48K, 49K, 50K, 51K, 52K, 53K, 54K, 55K | 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 |
| Stable Isotopes | Naturally occurring stable isotopes: 39K, 41K | Naturally occurring stable isotopes: 85Rb |
| Neutron Cross Section | 2.1 | 0.38 |
| Neutron Mass Absorption | 0.0018 | 0.0003 |
Chemical Properties: Ionization Energies and electron affinity
| Property | Potassium | Rubidium |
|---|---|---|
| Valence or Valency | 1 | 1 |
| Electronegativity | 0.82 Pauling Scale | 0.82 Pauling Scale |
| Electron Affinity | 48.4 kJ/mol | 46.9 kJ/mol |
| Ionization Energies | 1st: 418.8 kJ/mol 2nd: 3052 kJ/mol 3rd: 4420 kJ/mol 4th: 5877 kJ/mol 5th: 7975 kJ/mol 6th: 9590 kJ/mol 7th: 11343 kJ/mol 8th: 14944 kJ/mol 9th: 16963.7 kJ/mol 10th: 48610 kJ/mol 11th: 54490 kJ/mol 12th: 60730 kJ/mol 13th: 68950 kJ/mol 14th: 75900 kJ/mol 15th: 83080 kJ/mol 16th: 93400 kJ/mol 17th: 99710 kJ/mol 18th: 444880 kJ/mol 19th: 476063 kJ/mol | 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 |
Physical Properties
| Property | Potassium | Rubidium |
|---|---|---|
| Density | 0.856 g/cm3 | 1.532 g/cm3 |
| Molar Volume | 45.68 cm3/mol | 55.788 cm3/mol |
Elastic Properties | ||
| Young Modulus | - | 2.4 |
| Shear Modulus | 1.3 GPa | - |
| Bulk Modulus | 3.1 GPa | 2.5 GPa |
| Poisson Ratio | - | - |
Hardness - Tests to Measure of Hardness of Element | ||
| Mohs Hardness | 0.4 MPa | 0.3 MPa |
| Vickers Hardness | - | - |
| Brinell Hardness | 0.363 MPa | 0.216 MPa |
Electrical Properties | ||
| Electrical Conductivity | 14000000 S/m | 8300000 S/m |
| Resistivity | 7e-8 m Ω | 1.2e-7 m Ω |
| Superconducting Point | - | - |
Heat and Conduction Properties | ||
| Thermal Conductivity | 100 W/(m K) | 58 W/(m K) |
| Thermal Expansion | - | - |
Magnetic Properties | ||
| Magnetic Type | Paramagnetic | Paramagnetic |
| Curie Point | - | - |
| Mass Magnetic Susceptibility | 6.7e-9 m3/kg | 2.6e-9 m3/kg |
| Molar Magnetic Susceptibility | 2.62e-10 m3/mol | 2.22e-10 m3/mol |
| Volume Magnetic Susceptibility | 0.00000574 | 0.00000398 |
Optical Properties | ||
| Refractive Index | - | - |
Acoustic Properties | ||
| Speed of Sound | 2000 m/s | 1300 m/s |
Thermal Properties - Enthalpies and thermodynamics
| Property | Potassium | Rubidium |
|---|---|---|
| Melting Point | 336.53 K | 312.46 K |
| Boiling Point | 1032 K | 961 K |
| Critical Temperature | 2223 K | 2093 K |
| Superconducting Point | - | - |
Enthalpies | ||
| Heat of Fusion | 2.33 kJ/mol | 2.19 kJ/mol |
| Heat of Vaporization | 76.9 kJ/mol | 72 kJ/mol |
| Heat of Combustion | -182 J/(kg K) | - |
Regulatory and Health - Health and Safety Parameters and Guidelines
| Parameter | Potassium | Rubidium |
|---|---|---|
| CAS Number | CAS7440-09-7 | CAS7440-17-7 |
| RTECS Number | RTECSTS6460000 | RTECSVL8500000 |
| DOT Hazard Class | 4.3 | 4.3 |
| DOT Numbers | 2257 | 1423 |
| EU Number | - | - |
| NFPA Fire Rating | 3 | 3 |
| NFPA Health Rating | 3 | 2 |
| NFPA Reactivity Rating | 2 | - |
| NFPA Hazards | Water Reactive | Water Reactive |
| AutoIgnition Point | 440 °C | - |
| Flashpoint | - | - |
Compare With Other Elements
Compare Potassium and Rubidium with other elements of the periodic table.