1. Hydrogen has the atomic number 1.
2. Its chemical symbol is H.
3. It is the most abundant element in the Universe, making up around ¾ of its elemental mass.
4. Hydrogen’s melting point is −259.14 °C (−434.45 °F) and boiling point is −252.87 °C (−423.17 °F).
5. At standard temperature and pressure two atoms of the element bind to form dihydrogen, a colourless, odourless, tasteless, highly flammable diatomic gas with the formula H2.
6. Highly combustible it burns according to the following balanced equation.
2 H2(g) + O2 (g) → 2 H2O(g) + 572 kJ (286 kJ/mol)
7. There are 3 naturally occurring isotopes:- 1H (protium) with an abundance of 99.98%; 2H (deuterium) which is stable and thought to be a legacy of the Big Bang; and 3H (tritium) which is radioactive.
8. Henry Cavendish is normally given credit for the discovery of hydrogen in that in 1766, he was the first to recognize the gas given off in a reaction between a metal and an acid as a discrete substance. He later found in 1781 that the gas produced water when burned.
9. Antoine Lavoisier named the element in 1783. It is derived from the Greek for ‘hydro’ (water) and ‘genes’ (creator).
10. Hydrogen gas is rare in the Earth’s as its light weight allows it to escape the Earth’s gravity more easily than heavier gases. Despite this, hydrogen is the third most abundant element on the Earth’s surface after oxygen and silicon. Much of it is in the form of chemical compounds such as hydrocarbons and of course, water.
11. Hydrogen gas is produced by some bacteria and algae and is a natural component of flatus (wind, farts, or whatever you want to call it).
12. There are millions of known hydrocarbons – carbon and hydrogen containing compounds. The vast study of these organic compounds is known as organic chemistry.
13. Hydrogen can form compounds with elements such as fluorine, chlorine, bromine and iodine that are more electronegative than it. In these compounds, hydrogen takes on a slight positive charge.
14. When bonded to fluorine, oxygen, or nitrogen, hydrogen can participate in a form of strong non-covalent bonding called ‘hydrogen bonding’, which is critical to the stability of many biological molecules. It is also these ‘hydrogen bonds’ that account for many of the unusual properties of water (H2O).
15. Hydrogen also forms compounds with less electronegative elements, such as the metals and metalloids, in which it takes on a partial negative charge. These compounds are often known as ‘hydrides’.
16. Hydrogen is found in great abundance in stars like our Sun and gas giant planets such as Jupiter. It plays a crucial role in powering stars through fusion reactions.
17. In its plasma state, hydrogen’s electron and proton are not bound together, resulting in very high electrical conductivity and the production of light such as that we see from our Sun and other stars. These charged particles get blown out from our Sun (as a ‘solar wind’) through the solar system and interact with the Earth’s magnetosphere giving rise to the spectacular aurora Borealis and Australis in the upper atmosphere.
18. Hydrogen is being touted in some quarters as an ‘energy carrier’ that could help sustain economies rather than relying on burning carbon-based fuels. This could be done by reacting hydrogen with oxygen to release energy and produce water, however obtaining hydrogen in the first place is costly in terms of energy. An alternative method of generating energy in association with hydrogen would be through nuclear fusion. Whilst the Sun releases energy through the nuclear fusion of hydrogen, this process is incredibly difficult to control on Earth and seems quite far away rather than in our grasp.
19. Hydrogen does already power a variety of vehicles (usually at great expense) such as cars, buses, and even rockets like those that get the NASA space shuttle into space. Hydrogen can be burned in combustion engines in fundamentally the same method as traditional petrol cars. But, in the safer, more common fuel cell the hydrogen is reacted with oxygen to produce water and electricity, the latter of which is used to power an electric traction motor.
20. Having a density of 1/15th of the density of air, hydrogen was once widely used as a lifting gas in balloons and airships such as zeppelins and the infamous Hindenburg, but has since been replaced in this use by the inert gas, helium.