Periodic Table Element Comparison: Compare Elements - Hydrogen vs Helium
Compare Hydrogen and Helium 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 Hydrogen vs Helium with most reliable information about their properties, attributes, facts, uses etc. You can compare H vs He on more than 90 properties like electronegativity , oxidation state, atomic shells, orbital structure, Electronaffinity, physical states, electrical conductivity and many more. Hydrogen and Helium comparison table on more than 90 properties.
Hydrogen and Helium Comparison
Facts
| Name | Hydrogen | Helium |
|---|---|---|
| Atomic Number | 1 | 2 |
| Atomic Symbol | H | He |
| Atomic Weight | 1.00794 | 4.002602 |
| Phase at STP | Gas | Gas |
| Color | Colorless | Colorless |
| Metallic Classification | Other Nonmetal | Noble Gas |
| Group in Periodic Table | group 1 | group 18 |
| Group Name | lithium family | helium family or neon family |
| Period in Periodic Table | period 1 | period 1 |
| Block in Periodic Table | s -block | p -block |
| Electronic Configuration | 1s1 | 1s2 |
| Electronic Shell Structure (Electrons per shell) | 1 | 2 |
| Melting Point | 14.01 K | 0 K |
| Boiling Point | 20.28 K | 4.22 K |
| CAS Number | CAS1333-74-0 | CAS7440-59-7 |
| Neighborhood Elements | Neighborhood Elements of Hydrogen | Neighborhood Elements of Helium |
History
| Parameter | Hydrogen | Helium |
|---|---|---|
| History | The element Hydrogen was discovered by H. Cavendish in year 1766 in United Kingdom. Hydrogen derived its name from the Greek elements hydro- and -gen meaning 'water-forming'. | 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'. |
| Discovery | H. Cavendish (1766) | P. Janssen and N. Lockyer (1868) |
| Isolated | Paracelsus (1500) | W. Ramsay,T. Cleve, and N. Langlet (1895) |
Presence: Abundance in Nature and Around Us
Parts per billion (ppb) by weight / by atoms (1ppb =10^-7 %)
| Property | Hydrogen | Helium |
|---|---|---|
| Abundance in Universe | 750000000 / 930000000 | 230000000 / 72000000 |
| Abundance in Sun | 750000000 / 930000000 | 230000000 / 74000000 |
| Abundance in Meteorites | 24000000 / 170000000 | - / - |
| Abundance in Earth's Crust | 1500000 / 31000000 | 5.5 / 30 |
| Abundance in Oceans | 107800000 / 662000000 | 0.0072 / 0.011 |
| Abundance in Humans | 100000000 / 620000000 | - / - |
Crystal Structure and Atomic Structure
| Property | Hydrogen | Helium |
|---|---|---|
| Atomic Volume | 22.4135 cm3/mol | 22.4136 cm3/mol |
| Atomic Radius | 53 pm | 31 pm |
| Covalent Radius | 37 pm | 32 pm |
| Van der Waals Radius | 120 pm | 140 pm |
Atomic Spectrum - Spectral Lines | ||
| Emission Spectrum |  |  |
| Absorption Spectrum |  |  |
| Lattice Constant | 470, 470, 340 pm | 424.2, 424.2, 424.2 pm |
| Lattice Angle | π/2, π/2, 2 π/3 | π/2, π/2, π/2 |
| Space Group Name | P63/mmc | Fm_ 3m |
| Space Group Number | 194 | 225 |
| Crystal Structure | Simple Hexagonal  | Face Centered Cubic  |
Atomic and Orbital Properties
| Property | Hydrogen | Helium |
|---|---|---|
| Atomic Number | 1 | 2 |
| Number of Electrons (with no charge) | 1 | 2 |
| Number of Protons | 1 | 2 |
| Mass Number | 1.00794 | 4.002602 |
| Number of Neutrons | 0 | 2 |
| Shell structure (Electrons per energy level) | 1 | 2 |
| Electron Configuration | 1s1 | 1s2 |
| Valence Electrons | 1s1 | 1s2 |
| Oxidation State | -1, 1 | - |
| Atomic Term Symbol (Quantum Numbers) | 2S1/2 | 1S0 |
| Shell structure |  |  |
Isotopes and Nuclear Properties
Hydrogen has 2 stable naturally occuring isotopes while Helium has 2 stable naturally occuring isotopes.
| Parameter | Hydrogen | Helium |
|---|---|---|
| Known Isotopes | 1H, 2H, 3H, 4H, 5H, 6H, 7H | 3He, 4He, 5He, 6He, 7He, 8He, 9He, 10He |
| Stable Isotopes | Naturally occurring stable isotopes: 1H, 2H | Naturally occurring stable isotopes: 3He, 4He |
| Neutron Cross Section | 0.332 | 0.007 |
| Neutron Mass Absorption | 0.011 | 0.00001 |
Chemical Properties: Ionization Energies and electron affinity
| Property | Hydrogen | Helium |
|---|---|---|
| Valence or Valency | 1 | 0 |
| Electronegativity | 2.2 Pauling Scale | - |
| Electron Affinity | 72.8 kJ/mol | 0 kJ/mol |
| Ionization Energies | 1st: 1312 kJ/mol | 1st: 2372.3 kJ/mol 2nd: 5250.5 kJ/mol |
Physical Properties
| Property | Hydrogen | Helium |
|---|---|---|
| Density | 0.0000899 g/cm3 | 0.0001785 g/cm3 |
| Molar Volume | 22.4135 cm3/mol | 22.4136 cm3/mol |
Elastic Properties | ||
| Young Modulus | - | - |
| Shear Modulus | - | - |
| Bulk Modulus | - | - |
| Poisson Ratio | - | - |
Hardness - Tests to Measure of Hardness of Element | ||
| Mohs Hardness | - | - |
| Vickers Hardness | - | - |
| Brinell Hardness | - | - |
Electrical Properties | ||
| Electrical Conductivity | - | - |
| Resistivity | - | - |
| Superconducting Point | - | - |
Heat and Conduction Properties | ||
| Thermal Conductivity | 0.1805 W/(m K) | 0.1513 W/(m K) |
| Thermal Expansion | - | - |
Magnetic Properties | ||
| Magnetic Type | Diamagnetic | Diamagnetic |
| Curie Point | - | - |
| Mass Magnetic Susceptibility | -2.48e-8 m3/kg | -5.9e-9 m3/kg |
| Molar Magnetic Susceptibility | -4.999e-11 m3/mol | -2.36e-11 m3/mol |
| Volume Magnetic Susceptibility | -2.23e-9 | -1.05e-9 |
Optical Properties | ||
| Refractive Index | 1.000132 | 1.000035 |
Acoustic Properties | ||
| Speed of Sound | 1270 m/s | 970 m/s |
Thermal Properties - Enthalpies and thermodynamics
| Property | Hydrogen | Helium |
|---|---|---|
| Melting Point | 14.01 K | 0 K |
| Boiling Point | 20.28 K | 4.22 K |
| Critical Temperature | 32.97 K | 5.19 K |
| Superconducting Point | - | - |
Enthalpies | ||
| Heat of Fusion | 0.558 kJ/mol | 0.02 kJ/mol |
| Heat of Vaporization | 0.452 kJ/mol | 0.083 kJ/mol |
| Heat of Combustion | - | - |
Regulatory and Health - Health and Safety Parameters and Guidelines
| Parameter | Hydrogen | Helium |
|---|---|---|
| CAS Number | CAS1333-74-0 | CAS7440-59-7 |
| RTECS Number | RTECSMW8900000 | RTECSMH6520000 |
| DOT Hazard Class | 2.1 | 2.2 |
| DOT Numbers | 1966 | 1963 |
| EU Number | - | - |
| NFPA Fire Rating | 4 | 0 |
| NFPA Health Rating | 3 | 1 |
| NFPA Reactivity Rating | 0 | 0 |
| NFPA Hazards | - | - |
| AutoIgnition Point | 535.5 °C | - |
| Flashpoint | -18 °C | - |
Compare With Other Elements
Compare Hydrogen and Helium with other elements of the periodic table.
Compare Hydrogen with all Group 1 elementsCompare Hydrogen with LithiumCompare Hydrogen with SodiumCompare Hydrogen with PotassiumCompare Hydrogen with RubidiumCompare Hydrogen with CesiumCompare Hydrogen with Francium Compare Hydrogen with all Period 1 elementsCompare Hydrogen with all Other Nonmetal elements | Compare Helium with all Group 18 elementsHelium vs Neon ComparisonHelium vs Argon ComparisonHelium vs Krypton ComparisonHelium vs Xenon ComparisonHelium vs Radon ComparisonHelium vs Oganesson Comparison Compare Helium with all Period 1 elementsCompare Helium with all Noble Gas elements |