Hydrogen

Hydrogen, ₁H

Purpie glow in its plasma state
Hydrogen
Appearance	colorless gas
Standard atomic weight Ar, std(H)	[7000100784000000000♠1.00784, 7000100811000000000♠1.00811] conventional: 7000100800000000000♠1.008
Hydrogen in the periodic cairt
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium – ↑ H ↓ Li – ← hydrogen → helium
Atomic nummer (Z)	1
Group	group 1
Period	period 1
Block	s-block
Element category	Reactive nonmetal
Electron confeeguration	1s1
Electrons per shell	1
Pheesical properties
Colour	colorless
Phase at STP	gas
Meltin pynt	13.99 K ​(−259.16 °C, ​−434.49 °F)
Bylin pynt	20.271 K ​(−252.879 °C, ​−423.182 °F)
Density (at STP)	0.08988 g/L
when liquid (at m.p.)	0.07 g/cm3 (solit: 0.0763 g/cm3)
whan liquid (at b.p.)	0.07099 g/cm3
Treeple pynt	13.8033 K, ​7.041 kPa
Creetical pynt	32.938 K, 1.2858 MPa
Heat o fusion	(H2) 0.117 kJ/mol
Heat o vapourisation	(H2) 0.904 kJ/mol
Molar heat capacity	(H2) 28.836 J/(mol·K)
Vapour pressur P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 15 20
Atomic properties
Oxidation states	−1, +1 (an amphoteric oxide)
Electronegativity	Pauling scale: 2.20
Ionisation energies	1st: 1312.0 kJ/mol
Covalent radius	31±5 pm
Van der Waals radius	120 pm
Spectral lines o hydrogen
Ither properties
Naitural occurrence	primordial
Creestal structur	​hexagonal
Speed o soond	1310 m/s (gas, 27 °C)
Thermal conductivity	0.1805 W/(m·K)
Magnetic orderin	diamagnetic
Magnetic susceptibility	−3.98·10−6 cm3/mol (298 K)
CAS Nummer	12385-13-6 1333-74-0 (H2)
History
Diskivery	Henry Cavendish (1766)
Named by	Antoine Lavoisier (1783)
Main isotopes o hydrogen
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct 1H 99.98% stable 2H 0.02% stable 3H trace 12.32 y β− 3He

Hydrogen is the least wechtie atom in the universe, wi the atomic nummer o 1. It haes the seembol H, an a atomic wecht o 1.007 94 u. Hydrogen is aften lik tae burn an gin it burns in air, it jynes wi oxygen tae mak watter.

Hydrogen gas (H2) wis first made bi human haunds in the 16t century frae the kirnin o metals wi strang acids. In 1766-1781, Henry Cavendish wis the first ane ti ken that hydrogen gas is a discreet thing. Yin o the ideas for replacin motor fuel is tae uise hydrogen insteid, sin fuel maks orra gasses whan it burns, but hydrogen juist maks watter. Acause o this, we caw the element hydrogen, that beirs "watter-shaper" in Greek.

Tho hydrogen is the maist common atom in the universe, makin aboot 75% o the universe's maess. Maist hydrogen is grippit in starns, sae bodies canna get uise o it.