chemistry

Introduction & Top Questions
The scope of chemistry
- Analytical chemistry
- Inorganic chemistry
- Organic chemistry
- Biochemistry
- Polymer chemistry
- Physical chemistry
- Industrial chemistry
The methodology of chemistry
- Studies of molecular structure
  - Atoms and elements
  - Ionic and covalent bonding
  - Isomerism
- Investigations of chemical transformations
  - Basic factors
  - Energy and the first law of thermodynamics
  - Entropy and the second law of thermodynamics
  - Rates of reaction
Chemistry and society
The history of chemistry
- Philosophy of matter in antiquity
- Alchemy
- Phlogiston theory
- The chemical revolution
- Atomic and molecular theory
- Organic radicals and the theory of chemical structure
- Mendeleev’s periodic law
- The rise of physical chemistry
- Electronic theories of valence
- Biochemistry, polymers, and technology
- The instrumental revolution
- Organic chemistry in the 20th century
- Chemistry in the 21st century

References & Edit History Related Topics

Images, Videos & Interactives

molecular structure

Etching by Jacob de Gheyn III showing Thales of Miletus seated with a long beard, draped in robes, holding a compass over an open book with geometric diagrams.

Dmitri Mendeleev

Mendeleev's periodic table

A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors.

Diagram of the Bohr atomic model showing an electron moving in circular orbits with quantized energy levels around a central nucleus, alongside an energy level diagram illustrating electron transitions.

Diagram of the Rutherford atomic model for a neon atom, showing electrons orbiting a central nucleus. An inset magnifies the nucleus, depicting clustered protons and neutrons.

Diagram showing the formation of a polar covalent bond in a water molecule, with two hydrogen atoms bonding to one oxygen atom to form H2O, illustrating shared electrons and chemical reaction.

Nobel Prize: chemical elements discovered by winners

Learn how the invention of dynamite led, in part, to the global recognition of Martin Luther King, Jr., as a civil rights leader

At a Glance

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chemistry summary

Related Questions

molecular structure — molecular structure A ball-and-stick model of molecular structure, showing atoms bonded together.

chemistry

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Written by

Melvyn C. UsselmanAll

Fact-checked by

Britannica Editors

Last updated

Nov. 8, 2026 •History

chemistry, the science that deals with the properties, composition, and structure of substances (defined as elements and compounds), the transformations they undergo, and the energy that is released or absorbed during these processes. Every substance, whether naturally occurring or artificially produced, consists of one or more of the hundred-odd species of atoms that have been identified as elements. Although these atoms, in turn, are composed of more elementary particles, they are the basic building blocks...

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