 |
| General |
| Name | Helium |
| Symbol | He |
| Number | 2 |
| Group Number | 18 |
| Group | Noble Gas |
| Block | s |
| Density | 0.0001787 g/cm3 |
| Atomic Weight | 4.00260 g/mol |
| Atomic Volume | Nil |
| Discover | 1895 |
|
| States |
| State | Gas |
| Melting Point | 0.95 K |
| Boiling Point | 4.22 K |
| Triple Point | Nil |
| Critical Point | 5.19 K |
| Heat of Fusion | 0.0138 kJ/mol |
| Heat of Vaporization | 0.0829 kJ/mol |
|
| Energies |
| First Ionization Energy | 2372.3 kJ/mole |
| Second Ionization Energy | 5250.3 kJ/mole |
| Third Ionization Energy | Nil |
| Electronegativity | Nil |
| Electron Affinity | 0 kJ/mole |
| Specific Heat | 5.193 J/gK |
| Heat Atomization | 0 kJ/mole atoms |
|
| Oxidation and Electrons |
| Shells | 2 |
| Electron Configuration | 1s2 |
| Minimum Oxidation Number | 0 |
| Maximum Oxidation Number | 0 |
| Minimum Common Oxidation Number | 0 |
| Maximum Common Oxidation Number | 0 |
|
| Appearance and Characteristics |
| Crystal Structure | hexagonal close-packed |
| Characteristics | Inert, dens |
| Color | colorless |
| Uses | cryogenics, blimps |
| Hardness | mohs |
| Toxicity | No |
|
| Reactions |
| Reaction with Air | None |
| Reaction with 6M HCl | None |
| Reaction with 15M HNO3 | None |
| Reaction with 6M NaOH | None |
|
| Other Forms |
| Number of Isotopes | 2 |
| Hydride | None |
| Oxide | None |
| Chloride | None |
|
| Radius |
| Atomic Radius | 31 pm |
| Ionic Radius (1+ ion) | Nil |
| Ionic Radius (1- ion) | Nil |
| Ionic Radius (2+ ion) | Nil |
| Ionic Radius (2- ion) | Nil |
| Ionic Radius (3+ ion) | Nil |
|
| Conductivity |
| Thermal Conductivity | 0.15 J/m-sec-deg |
| Electrical Conductivity | 1/mohm-cm |
| Polarizability | 0.198 A3 |
|
| Abundance |
| Source | Natural gas, air |
| Relation Abundance Solar System | 9.435 log |
| Abundance Earth's Crust | -2.1 log |
|
