| A | B |
|---|---|
| Purple glow in hydrogen’s plasma state. | … |
| Hydrogen | … |
| Appearance | Colorless gas |
| Standard atomic weight A °(H) | … |
| • [1.007 84 , 1.008 11] 1 • 1.0080 ± 0.0002 (abridged) 2 | |
| Hydrogen in the periodic table | … |
| – ↑ H ↓ Li (none) ← hydrogen → helium | … |
| Atomic number (Z) | 1 |
| Group | group 1: hydrogen and alkali metals |
| Period | period 1 |
| Block | s-block |
| Electron configuration | 1s |
| Electrons per shell | 1 |
| Physical properties | … |
| Phase at STP | gas |
| Melting point | (H) 13.99 K (−259.16 °C, −434.49 °F) |
| Boiling point | (H) 20.271 K (−252.879 °C, −423.182 °F) |
| Density (at STP) | 0.08988 g/L |
| when liquid (at m.p.) | 0.07 g/cm (solid: 0.0763 g/cm)3 |
| when liquid (at b.p.) | 0.07099 g/cm |
| Triple point | 13.8033 K, 7.041 kPa |
| Critical point | 32.938 K, 1.2858 MPa |
| Heat of fusion | (H) 0.117 kJ/mol |
| Heat of vaporization | (H) 0.904 kJ/mol |
| Molar heat capacity | 14.418 J/(mol·K) (H) 28.836 J/(mol·K) (H) |
| Specific heat capacity | 14303.571 J/(kg·K) (H) |
| Vapor pressure | … |
| Atomic properties | … |
| Oxidation states | common: −1, +1 |
| Electronegativity | Pauling scale: 2.20 |
| Ionization energies | • 1st: 1312.0 kJ/mol |
| Covalent radius | 31±5 pm |
| Van der Waals radius | 120 pm |
| Spectral lines of hydrogen | … |
| Other properties | … |
| Natural occurrence | primordial |
| Crystal structure | hexagonal (hP4) |
| Lattice constants | a = 378.97 pm c = 618.31 pm (at triple point)4 |
| Thermal conductivity | 0.1805 W/(m⋅K) |
| Magnetic ordering | diamagnetic5 |
| Molar magnetic susceptibility | −3.98×10 cm/mol (298 K)6 |
| Speed of sound | 1310 m/s (gas, 27 °C) |
| CAS Number | 12385-13-6 1333-74-0 (H) |
| History | … |
| Naming | name means ‘water-former’ in Greek |
| Discovery and first isolation | Henry Cavendish789 (1766) |
| Named by | Antoine Lavoisier710 (1783) |
| Isotopes of hydrogen | … |
| Abundance of deuterium is highly variable | … |
Hydrogen, H
(echo:: @ ᯤ)
Footnotes
-
“Standard Atomic Weights: Hydrogen”. CIAAW. 2009. ↩
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Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). “Standard atomic weights of the elements 2021 (IUPAC Technical Report)”. Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075. ↩
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Wiberg, Egon; Wiberg, Nils; Holleman, Arnold Frederick (2001). Inorganic chemistry. Academic Press. p. 240. ISBN 978-0123526519. ↩
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Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9. ↩
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Lide, D. R., ed. (2005). “Magnetic susceptibility of the elements and inorganic compounds”. CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 978-0-8493-0486-6. ↩
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Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 978-0-8493-0464-4. ↩
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Miśkowiec, Paweł (April 2023). “Name game: The naming history of the chemical elements—part 1—from antiquity till the end of 18th century”. Foundations of Chemistry. 25 (1): 29–51. doi:10.1007/s10698-022-09448-5. ↩ ↩2
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Emsley, John (2001). Nature’s Building Blocks. Oxford: Oxford University Press. pp. 183–191. ISBN 978-0-19-850341-5. ↩
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“Hydrogen”. Van Nostrand’s Encyclopedia of Chemistry. Wylie-Interscience. 2005. pp. 797–799. ISBN 978-0-471-61525-5. ↩
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Stwertka, Albert (1996). A Guide to the Elements. Oxford University Press. pp. 16–21. ISBN 978-0-19-508083-4. ↩