chemical properties – Hydrogen symbol, electronic configuration, density



Hydrogen is the lightest and most abundant chemical element.The most common isotope of hydrogen is protium with a single proton and no neutrons. 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 identifying the gas from a metal-acid reaction as “phlogiston”, meaning “flammable air” and further finding in 1781 that the gas produces water when burned. He is usually given credit for its discovery as an element. In 1783, Antoine Lavoisier gave the element the name hydrogen when he and Laplace reproduced Cavendish’s finding that water is produced when hydrogen is burned. Large quantities of hydrogen are needed in the petroleum and chemical industries. The largest application of hydrogen is for the processing of fossil fuels, and in the production of ammonia. It is used as a hydrogenating agent, particularly in increasing the level of saturation of unsaturated fats and oils, and in the production of methanol. It is similarly the source of hydrogen in the manufacture of hydrochloric acid. It is also used as a reducing agent of metallic ores. It is commonly used in power stations, as a coolant in generators, due to its specific heat capacity being considerably higher than any other gas.

Chemical Properties.

Appearance Colorless Gas
Atomic Number 1
Atomic Weight 1.00794 g/mol
Block S
Boiling Point −252.87 °C
CAS Number 1333-74-0
Class 2.1
Crystal Structure Hexagonal
Density 0.899 g/cm3
EINECS Number 215-605-7
Electron Configuration 1s1
Group 1
Ionization Energy 1312 kJ/mol
Melting Point −259.14 °C
NFPA 704 H-0,F-4,R-0,C-NA
Oxidation State 1,-1
Period 1
RTECS Number MW8900000
Solubility 0.00017 g/100 ml
Symbol H


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