Curated category
Reactive nonmetals
- NitrogenScottish physician Daniel Rutherford isolated a new gas in 1772 during experiments at the University of Edinburgh. He called this substance noxious air…
- OxygenOxygen is the third most abundant chemical element in the universe, trailing only hydrogen and helium. About 0.9% of the Sun's mass consists of oxygen.
- HydrogenAbout 75% of all normal matter in the universe consists of hydrogen. This element formed roughly 370,000 years after the Big Bang when the expanding cosmos…
- SeleniumIn 1817, Jöns Jacob Berzelius and Johan Gottlieb Gahn stood before a red solid precipitate in the lead chambers of their chemistry plant near Gripsholm…
- CarbonCarbon is the sixth element, with a ground-state electron configuration of 1s22s22p2. Its four outer electrons are valence electrons that allow it to form up…