Quiz: Remember the definition of mal de mer?

atomic theory

Physics, Chemistry. any of several theories describing the structure, behavior, and other properties of the atom and its component parts.
Philosophy, atomism (def 1).
1840-50 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
Cite This Source
Examples from the web for atomic theory
  • The dyestuffs industry and the chemical industry more generally were the products of the atomic theory and what followed from it.
  • It is as factual an explanation of the universe as the atomic theory of matter or the germ theory of disease.
  • Not unless you also ask whether basic atomic theory is wrong.
  • atomic theory offers another example of delayed confirmation.
  • Neither does atomic theory of matter, the heliocentric model of the solar system, or plate tectonics.
  • And, as was the case with atomic theory, one cannot predict how long such a leap will take.
  • Describe the sequence of selected discoveries, which resulted in modern atomic theory.
  • Students will also investigate direct and indirect evidence as they explore atomic theory and conservation of matter.
  • Charge radii were extracted from the measured isotope shifts with the help of precision atomic theory calculations.
British Dictionary definitions for atomic theory

atomic theory

any theory in which matter is regarded as consisting of atoms, esp that proposed by John Dalton postulating that elements are composed of atoms that can combine in definite proportions to form compounds
the current concept of the atom as an entity with a definite structure See atomic structure
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
Encyclopedia Article for atomic theory

ancient philosophical speculation that all things can be accounted for by innumerable combinations of hard, small, indivisible particles (called atoms) of various sizes but of the same basic material; or the modern scientific theory of matter according to which the chemical elements that combine to form the great variety of substances consist themselves of aggregations of similar subunits (atoms) possessing nuclear and electron substructure characteristic of each element. The ancient atomic theory was proposed in the 5th century BC by the Greek philosophers Leucippus and Democritus and was revived in the 1st century BC by the Roman philosopher and poet Lucretius. The modern atomic theory, which has undergone continuous refinement, began to flourish at the beginning of the 19th century with the work of the English chemist John Dalton. The experiments of the British physicist Ernest Rutherford in the early 20th century on the scattering of alpha particles from a thin gold foil established the Rutherford atomic model of an atom as consisting of a central, positively charged nucleus containing nearly all the mass and surrounded by a cloud of negatively charged planetlike electrons.

Learn more about atomic theory with a free trial on
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
Cite This Source

Word of the Day

Difficulty index for atomic theory

Few English speakers likely know this word

Word Value for atomic

Scrabble Words With Friends