1
H
1.0079
Hydrogen
Nonmetal
Group 1
Period 1
Block s
Gas
Hydrogen is a chemical element of the periodic table with chemical symbol H and atomic number 1 with an atomic weight of 1.0079 u and is classed as nonmetal and is part of group 1 (alkali metal). Hydrogen is gas at room temperature.
Hydrogen in the periodic table
| Symbol | H |
| Atomic number | 1 |
| Group | 1 (Alkali metal) |
| Period | 1 |
| Block | s |
| Classification | Nonmetal |
| Appearance | Colorless gas |
| Color | Colorless |
| Number of protons | 1 p+ |
| Number of neutrons | 0 n0 |
| Number of electrons | 1 e- |
From Wikipedia, the free encyclopediaHydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 1.00794 u, hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass.
Physical properties
| Phase at STP | Gas |
| Density | 0.08988 g/cm3 |
| Atomic weight | 1.0079 u |
Thermal properties
| Melting point | 13.99 K -259.16 °C -434.488 °F |
| Boiling point | 20.271 K -252.879 °C -423.1822 °F |
| Heat of vaporization | 0.4581 kJ/mol |
Atomic properties
| Electronegativity (Pauling Scale) | 2.2 |
| Electron affinity | 72.769 kJ/mol |
| Oxidation states | −1, +1 (an amphoteric oxide) |
| Ionization energies |
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Electron configuration for hydrogen
Electron configuration Shorthand configuration | 1s1 | ||
| Full configuration | 1s1 | ||
Electron configuration chart |
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| Electrons per shell | 1 | ||
| Valence electrons | 1 | ||
| Valency electrons | 1 | ||
| Bohr model | Figure: Shell diagram of Hydrogen (H) atom. | ||
Orbital Diagram |
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The history of Hydrogen
| Discovery and first isolation | Henry Cavendish (1766) |
| Named by | Antoine Lavoisier (1783) |
Discovery of hydrogen In 1671, Robert Boyle discovered and described the reaction between iron filings and dilute acids, which results in the production of hydrogen gas. In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metal-acid reaction "inflammable air". He speculated that "inflammable air" was in fact identical to the hypothetical substance called "phlogiston" and further finding in 1781 that the gas produces water when burned. He is usually given credit for the discovery of hydrogen as an element. In 1783, Antoine Lavoisier gave the element the name hydrogen (from the Greek ὑδρο- hydro meaning "water" and -γενής genes meaning "former") when he and Laplace reproduced Cavendish's finding that water is produced when hydrogen is burned. | |
| Original word | hydor + genes |
| Language of origin | Greek |
| Name source | Properties |
| Meaning | “Water-forming” |
Naming The name is derived from the Greek hyrdo- (ὑδρο) meaning "water" and -genes (γενής) meaning "former". | |