Periodic Table

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Periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties, whose structure shows periodic trends. Generally, within one row (period) the elements are metals to the left, and non-metals to the right, with the elements having similar chemical behaviours placed in the same column. Table rows are commonly called periods and columns are called groups. Six groups have accepted names as well as assigned numbers: for example, group 17 elements are the halogens; and group 18 are the noble gases. Also displayed are four simple rectangular areas or blocks associated with the filling of different atomic orbitals.

The organization of the periodic table can be used to derive relationships between the various element properties, but also the predicted chemical properties and behaviours of undiscovered or newly synthesized elements. Russian chemist Dmitri Mendeleev was the first to publish a recognizable periodic table in 1869, developed mainly to illustrate periodic trends of the then-known elements. He also predicted some properties of unidentified elements that were expected to fill gaps within the table. Most of his forecasts proved to be correct. Mendeleev’s idea has been slowly expanded and refined with the discovery or synthesis of further new elements and the development of new theoretical models to explain chemical behaviour. The modern periodic table now provides a useful framework for analyzing chemical reactions, and continues to be widely used in chemistry, nuclear physics and other sciences.

All the elements from atomic numbers 1 (hydrogen) through 118 (oganesson) have been either discovered or synthesized, completing the first seven rows of the periodic table. The first 98 elements exist in nature, although some are found only in trace amounts and others were synthesized in laboratories before being found in nature. Elements 99 to 118 have only been synthesized in laboratories or nuclear reactors. The synthesis of elements having higher atomic numbers is currently being pursued: these elements would begin an eighth row, and theoretical work has been done to suggest possible candidates for this extension. Numerous synthetic radionuclides of naturally occurring elements have also been produced in laboratories. — Wikipedia

Encyclopædia Britannica


Physics Databases & Periodic Tables (Martindale’s Reference Desk)



UNESCO and 1001 Inventions Launch Journeys from Alchemy to Chemistry (IYT2019, UNESCO)

The International Year of the Periodic Table (2019 IYPT)

An unelementary affair: 150 years of the periodic table (Robert P Crease, Physics World)
How the periodic table went from a sketch to an enduring masterpiece (Tom Siegfried, Science News)

Setting the table (Phillip Szuromi, Science Magazine)
Ordering the elements (Michael D. Gordin, Science Magazine)

The Periodic Table of Elements in Pictures and Words (Keith Enevoldsen,
This Awesome Periodic Table Tells You How to Actually Use All Those Elements (BEC CREW, Science Alert)

Periodic Table of Elements (International Union of Pure and Applied Chemistry)
Interactive Periodic Table of Elements (Los Alamos National Laboratory)
Periodic Table (American Chemical Society)




Solving the puzzle of the periodic table – Eric Rosado
Brief history of the development of the periodic table (Western Oregon University)

The periodic tables we almost had (Mark Lorch, Quartz)
Alternate Periodic Table Designs (Western Oregon University)
The Internet Database of Periodic Tables

Periodic Videos (YouTube Channel)



WorldCat, Library of Congress, UPenn Online Books, Open Library




Periodic Table (For Kids! YouTube Channel)

Periodic Table and the Elements (Chem4Kids)


Crash Course Chemistry (YouTube)

Chemistry Courses (MIT Open Courseware)
Chemistry Courses (Coursera)
OER Commons: Open Educational Resources



Chemists and Materials Scientists (Occupational Outlook Handbook)


International Union of Pure and Applied Chemistry
American Chemical Society
Royal Society of Chemistry
Chemical Structure Association Trust


Pure and Applied Chemistry (International Union of Pure and Applied Chemistry)
Journal of the American Chemical Society
Nature Chemistry
Scientific American
NPR Archives




The Quest for Superheavy Elements and the Island of Stability (Christoph E. Düllmann and Michael Block, Scientific American)



My Favourite Element (YouTube Channel, The Royal Institution)
Periodic Videos (YouTube Channel)


Tom Lehrer at 90: a life of scientific satire (Andrew Robinson, Nature)


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Here are links to pages about closely related subjects.

Knowledge Realm


Law (Constant) Relativity
Force Gravity, Electromagnetism (Light, Color)
Matter (Microscope) Molecule, Atom (Periodic Table), Particle

Universe (Astronomical Instrument)
Galaxy Milky Way, Andromeda
Planetary System Star, Brown Dwarf, Planet, Moon

Our Neighborhood
Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Trans-Neptunian Object
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid


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