Save guides, add subjects and pick up where you left off with your BBC account. An element's atomic number defines it. An element with 17 protons will always be chlorine. However an element's mass ...

Heavy water is a form of water with a unique atomic structure and properties ... molecule of heavy water contains two hydrogen atoms and one oxygen atom. The difference, though, lies in the ...

Everyone at that time imagined the atom as a "plum pudding ... of light emitted by real hydrogen atoms. Bohr's theory that electrons existed in set orbits around the nucleus was the key to ...

Without the acidic hydrogen atoms it is ... probably impossible to build this structure with a ribose sugar in place of the deoxyribose, as the extra oxygen atom would make too close a van der ...

This image illustrates the general structure of an amino acid.The central carbon atom (C) is bonded to a hydrogen atom (H), an amino group (NH2), a carboxyl group (COOH), and a variable side chain (R ...

A controversial take in this world is that hydrogen binding energy might not be the first way to go anymore. Conventional thinking holds that the metal site in single atom catalysts (SACs ...