The chemical elements are the fundamental substances that cannot be broken down by ordinary chemical means. Each element is defined by its atomic number, the number of protons in its nucleus, and together they form the basis of modern chemistry. As of now, 118 distinct elements have been confirmed and named, ranging from hydrogen (the lightest) to oganesson (the heaviest officially recognized). A complete arranged reference is commonly shown in the periodic table.

Organization and major categories

The periodic table orders elements by increasing atomic number and groups them by recurring chemical properties. Major categories include:

  • Nonmetals (e.g., hydrogen, carbon, oxygen) — often gases or brittle solids important for life.
  • Metals (e.g., iron, copper, gold) — typically conductive, malleable, used in construction and technology.
  • Metalloids (e.g., silicon) — intermediate properties, crucial in electronics.
  • Noble gases (e.g., helium, neon) — largely inert monatomic gases.
  • Lanthanides and actinides — the inner transition series, including rare-earth elements and many radioactive actinides.

History and naming

Elements were identified gradually: a few were known to ancient civilizations (gold, silver, carbon) while most were discovered between the 18th and 20th centuries as techniques improved. In the 20th century, scientists synthesized new, short-lived elements in laboratories. Names reflect a variety of sources—ancient words, places, properties, or people—and are ratified by international bodies that standardize chemical nomenclature.

Isotopes—atoms of the same element with different numbers of neutrons—affect stability and applications. Many elements have both stable and radioactive isotopes; some heavy elements exist only as synthetic isotopes created in particle accelerators or nuclear reactors.

Uses and significance

Elements underpin technology, medicine, and industry. Examples include iron and aluminum in construction, silicon in semiconductors, uranium and plutonium in nuclear energy, and technetium in medical imaging. Trace elements are essential for biology—iron in blood, iodine for thyroid function—while rare elements enable modern electronics and clean-energy technologies.

Understanding the list of elements and their properties is central to chemistry, materials science, and related fields. For a full tabulated list with atomic numbers, symbols, and key properties, consult a modern periodic table reference such as the one linked above.