Periodic Table Element Comparison: Compare Elements - Helium vs Molybdenum
Compare Helium and Molybdenum
Compare Helium and Molybdenum 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 Helium vs Molybdenum with most reliable information about their properties, attributes, facts, uses etc. You can compare He vs Mo on more than 90 properties like electronegativity , oxidation state, atomic shells, orbital structure, Electronaffinity, physical states, electrical conductivity and many more.
Facts
| Name | Helium | Molybdenum |
| Atomic Number | 2 | 42 |
| Atomic Symbol | He | Mo |
| Atomic Weight | 4.002602 | 95.94 |
| Phase at STP | Gas | Solid |
| Color | Colorless | Gray |
| Metallic Classification | Noble Gas | Transition Metal |
| Group in Periodic Table | group 18 | group 6 |
| Group Name | helium family or neon family | chromium family |
| Period in Periodic Table | period 1 | period 5 |
| Block in Periodic Table | p -block | d -block |
| Electronic Configuration | 1s2 | [Kr] 4d5 5s1 |
| Electronic Shell Structure (Electrons per shell) | 2 | 2, 8, 18, 13, 1 |
| Melting Point | 0 K | 2896 K |
| Boiling Point | 4.22 K | 4912 K |
| CAS Number | CAS7440-59-7 | CAS7439-98-7 |
| Neighborhood Elements | Neighborhood Elements of Helium | Neighborhood Elements of Molybdenum |
History
| History | The element Helium was discovered by P. Janssen and N. Lockyer in year 1868 in Sweden and United Kingdom. Helium derived its name from the Greek word helios, meaning 'sun'. | The element Molybdenum was discovered by W. Scheele in year 1778 in Sweden. Molybdenum derived its name from the Greek word molybdos meaning 'lead'. |
| Discovery | P. Janssen and N. Lockyer (1868) | W. Scheele (1778) |
| Isolated | W. Ramsay,T. Cleve, and N. Langlet (1895) | J. Hjelm (1781) |
Presence: Abundance in Nature and Around Us
Parts per billion (ppb) by weight / by atoms (1ppb =10^-7 %)
| Abundance in Universe | 230000000 / 72000000 | 5 / 0.1 |
| Abundance in Sun | 230000000 / 74000000 | 9 / 0.1 |
| Abundance in Meteorites | - / - | 1200 / 250 |
| Abundance in Earth's Crust | 5.5 / 30 | 1100 / 230 |
| Abundance in Oceans | 0.0072 / 0.011 | 10 / 0.64 |
| Abundance in Humans | - / - | 100 / 7 |
Crystal Structure and Atomic Structure
| Atomic Volume | 22.4136 cm3/mol | 9.333 cm3/mol |
| Atomic Radius | 31 pm | 190 pm |
| Covalent Radius | 32 pm | 145 pm |
| Van der Waals Radius | 140 pm | - |
| Atomic Spectrum |  |  |
| Lattice Constant | 424.2, 424.2, 424.2 pm | 314.7, 314.7, 314.7 pm |
| Lattice Angle | π/2, π/2, π/2 | π/2, π/2, π/2 |
| Space Group Name | Fm_ 3m | Im_ 3m |
| Space Group Number | 225 | 229 |
| Crystal Structure | Face Centered Cubic  | Body Centered Cubic  |
Atomic and Orbital Properties
| Atomic Number | 2 | 42 |
| Number of Electrons (with no charge) | 2 | 42 |
| Number of Protons | 2 | 42 |
| Mass Number | 4.002602 | 95.94 |
| Number of Neutrons | 2 | 54 |
| Shell structure (Electrons per energy level) | 2 | 2, 8, 18, 13, 1 |
| Electron Configuration | 1s2 | [Kr] 4d5 5s1 |
| Valence Electrons | 1s2 | 4d5 5s1 |
| Oxidation State | - | 4, 6 |
| Atomic Term Symbol (Quantum Numbers) | 1S0 | 7S3 |
| Shell structure |  |  |
Isotopes and Nuclear Properties
Helium has 2 stable naturally occuring isotopes while Molybdenum has 6 stable naturally occuring isotopes.
| Known Isotopes | 3He, 4He, 5He, 6He, 7He, 8He, 9He, 10He | 83Mo, 84Mo, 85Mo, 86Mo, 87Mo, 88Mo, 89Mo, 90Mo, 91Mo, 92Mo, 93Mo, 94Mo, 95Mo, 96Mo, 97Mo, 98Mo, 99Mo, 100Mo, 101Mo, 102Mo, 103Mo, 104Mo, 105Mo, 106Mo, 107Mo, 108Mo, 109Mo, 110Mo, 111Mo, 112Mo, 113Mo, 114Mo, 115Mo |
| Stable Isotopes | Naturally occurring stable isotopes: 3He, 4He | Naturally occurring stable isotopes: 92Mo, 94Mo, 95Mo, 96Mo, 97Mo, 98Mo |
| Neutron Cross Section | 0.007 | 2.6 |
| Neutron Mass Absorption | 0.00001 | 0.0009 |
Chemical Properties: Ionization Energies and electron affinity
| Valence or Valency | 0 | 6 |
| Electronegativity | - | 2.16 Pauling Scale |
| Electron Affinity | 0 kJ/mol | 71.9 kJ/mol |
| Ionization Energies | 1st: 2372.3 kJ/mol 2nd: 5250.5 kJ/mol | 1st: 684.3 kJ/mol 2nd: 1560 kJ/mol 3rd: 2618 kJ/mol 4th: 4480 kJ/mol 5th: 5257 kJ/mol 6th: 6640.8 kJ/mol 7th: 12125 kJ/mol 8th: 13860 kJ/mol 9th: 15835 kJ/mol 10th: 17980 kJ/mol 11th: 20190 kJ/mol 12th: 22219 kJ/mol 13th: 26930 kJ/mol 14th: 29196 kJ/mol 15th: 52490 kJ/mol 16th: 55000 kJ/mol 17th: 61400 kJ/mol 18th: 67700 kJ/mol 19th: 74000 kJ/mol 20th: 80400 kJ/mol 21st: 87000 kJ/mol 22nd: 93400 kJ/mol 23rd: 98420 kJ/mol 24th: 104400 kJ/mol 25th: 121900 kJ/mol 26th: 127700 kJ/mol 27th: 133800 kJ/mol 28th: 139800 kJ/mol 29th: 148100 kJ/mol 30th: 154500 kJ/mol |
Physical Properties
| Density | 0.0001785 g/cm3 | 10.28 g/cm3 |
| Molar Volume | 22.4136 cm3/mol | 9.333 cm3/mol |
Elastic Properties | ||
| Young Modulus | - | 329 |
| Shear Modulus | - | 20 GPa |
| Bulk Modulus | - | 230 GPa |
| Poisson Ratio | - | 0.31 |
Hardness - Tests to Measure of Hardness of Element | ||
| Mohs Hardness | - | 5.5 MPa |
| Vickers Hardness | - | 1530 MPa |
| Brinell Hardness | - | 1500 MPa |
Electrical Properties | ||
| Electrical Conductivity | - | 20000000 S/m |
| Resistivity | - | 5e-8 m Ω |
| Superconducting Point | - | 0.915 |
Heat and Conduction Properties | ||
| Thermal Conductivity | 0.1513 W/(m K) | 139 W/(m K) |
| Thermal Expansion | - | 0.0000048 /K |
Magnetic Properties | ||
| Magnetic Type | Diamagnetic | Paramagnetic |
| Curie Point | - | - |
| Mass Magnetic Susceptibility | -5.9e-9 m3/kg | 1.17e-8 m3/kg |
| Molar Magnetic Susceptibility | -2.36e-11 m3/mol | 1.122e-9 m3/mol |
| Volume Magnetic Susceptibility | -1.05e-9 | 0.0001203 |
Optical Properties | ||
| Refractive Index | 1.000035 | - |
Acoustic Properties | ||
| Speed of Sound | 970 m/s | 6190 m/s |
Thermal Properties - Enthalpies and thermodynamics
| Melting Point | 0 K | 2896 K |
| Boiling Point | 4.22 K | 4912 K |
| Critical Temperature | 5.19 K | - |
| Superconducting Point | - | 0.915 |
Enthalpies | ||
| Heat of Fusion | 0.02 kJ/mol | 36 kJ/mol |
| Heat of Vaporization | 0.083 kJ/mol | 600 kJ/mol |
| Heat of Combustion | - | - |
Regulatory and Health - Health and Safety Parameters and Guidelines
| CAS Number | CAS7440-59-7 | CAS7439-98-7 |
| RTECS Number | RTECSMH6520000 | RTECSQA4680000 |
| DOT Hazard Class | 2.2 | 4.1 |
| DOT Numbers | 1963 | 3089 |
| EU Number | - | - |
| NFPA Fire Rating | 0 | 3 |
| NFPA Hazards | - | - |
| NFPA Health Rating | 1 | 1 |
| NFPA Reactivity Rating | 0 | 0 |
| AutoIgnition Point | - | - |
| Flashpoint | - | - |