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 ...

In fact, each gene in cellular DNA contains the code for a unique protein structure ... carbon atom linked to an amino group, a carboxyl group, a hydrogen atom, and a variable component called ...

When quantum electrodynamics, the quantum field theory of electrons and photons, was being developed after World War II, one of the major challenges for theorists was calculating a value for the Lamb ...

The typical size of atoms and small molecules is around 1 × 10-10 m (0.1 nm). For example: diameter of a hydrogen atom, H 1.0 × 10-10 m width of a hydrogen molecule, H 2 2.9 × 10-10 m ...

An element's atomic number defines it. An element with 17 protons will always be chlorine. However an element's mass numbers can vary, which means that it can have different numbers of neutrons.

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 ...