| ChemGlobe: Hydrogen: Electronic, thermal, and steric data along with basic information. |
| Chemical of the Week: Hydrogen: Equations for reactions between hydrogen and other substances. |
| ChemicalElements.com: Hydrogen: Basic information, atomic structure, and table of isotopes. |
| EnvironmentalChemistry.com: Hydrogen: Atomic structure, chemical and physical properties, and table of nuclides. |
| Especiál Gas Inc.: Hydrogen: Numeric data, uses, and general information. |
| Hydrogen: Data tables and historic information. |
| Hydrogen Energies and Spectrum: The Bohr model for an electron transition in hydrogen between quantized energy levels with different quantum numbers n yields a photon by emission with quantum energy. |
| It's Elemental: Hydrogen: Basic physical and historical information. |
| LANL: Hydrogen: Brief reference on the element includes discussion of the sources of hydrogen, its current uses, and potential for new energy applications. |
| Lenntech: Hydrogen: Physical data, chemical properties, health and environmental effects. |
| Visual Elements: Hydrogen: General and physical information, uses, and key isotopes. |
| Wikipedia: Hydrogen: Properties of the element, including its history, applications, and characteristics. |
Classical
