R

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
radiation
Energy emitted from some object.
radical
A species with an odd number of electrons; formerly called free radical.
radioactivity
The spontaneous emission of particles and/or energy from atomic nuclei.
radioisotope
Contraction for words "radioactive isotope" of an element.
reactant
A starting material in a chemical reaction.
reactivity
The degree to which a substance will respond to a stimulus or interact with another substance.
receptor
Protein molecules on the surface of cell membranes used for communication between cells.
recycling
To treat or process waste materials so as to make them suitable for reuse. The key to successful recycling of materials contained in refuse lies in the separation of recyclable components from the main bulk of the waste.
reducing
The gain of electrons by an atom, ion, or molecule.
reduction
A gain of electrons; a decrease in oxidation state.
refrigerant
A chemical used in refrigeration, to keep substances cool.
resistance
The opposition of a substance to the passage through it of a steady electric current.From Ohm's Law, R = E/I, the resistance equals the voltage of the cell divided by the current flow.
resonance structure
Possible structures of a molecule for which more than one electron-dot structure can be written, which differ in the bond pairs between atoms.

Glossary created by David Shaw (Madison Area Technical College) for The Chemistry Place.

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