Benutzer:Fmrauch/Baustelle

ACHTUNG - DIES IST EIN TEST

Chemisches Periodensystem

Nummer	Element
1	{{{2}}}, WasserstoffWasserstoff
2	{{{2}}}, HeliumHelium
3	{{{2}}}, LithiumLithium
4	{{{2}}}, BerylliumBeryllium
5	{{{2}}}, BorBor
6	{{{2}}}, KohlenstoffKohlenstoff
7	{{{2}}}, StickstoffStickstoff
8	{{{2}}}, SauerstoffSauerstoff
9	{{{2}}}, FluorFluor
10	{{{2}}}, NeonNeon
92	{{{2}}}, UranUran

Hydrogen (Vorlage:IPAc-en Vorlage:Respell) is a chemical element with atomic number 1. The symbol is H. With an average atomic weight of ... hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly composed of hydrogen in its plasma state. Naturally occurring elemental hydrogen is relatively rare on Earth.

The most common isotope of hydrogen is ¹H) with a single proton. In ionic compounds it can take a negative charge, written as H⁻), or as a positively charged species H⁺. In reality, hydrogen cations in ionic compounds always occur as more complex species. Hydrogen forms compounds with most elements and most organic compounds. It plays a particularly important role in acid-base chemistry with many reactions exchanging protons between soluble molecules.