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)
These are organized by a classification scheme developed exclusively for Cosma. More…
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
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Physicists reverse time using quantum computer
on March 13, 2019 at 11:27 am
Researchers from the Moscow Institute of Physics and Technology teamed up with colleagues from the U.S. and Switzerland and returned the state of a quantum computer a fraction of a second into the past. They also calculated the probability that an electron in empty interstellar space will spontaneously travel back into its recent past. The study is published in Scientific Reports. […]
Physicists solve a beta-decay puzzle with...
on March 11, 2019 at 4:00 pm
An international collaboration including scientists at the Department of Energy's (DOE's) Oak Ridge National Laboratory (ORNL) solved a 50-year-old puzzle that explains why beta decays of atomic nuclei are slower than what is expected based on the beta decays of free neutrons. […]
Hydrogen fuels rockets, but what about power for...
on March 11, 2019 at 11:27 am
Hydrogen is the first element on the periodic table. In its pure form hydrogen is a light, colourless gas, but forms a liquid at very low temperatures. […]
Lightweight of periodic table plays big role in...
on March 4, 2019 at 2:10 pm
Although hydrogen is the lightweight of the chemical elements, it packs a real punch when it comes to its role in life and its potential as a solution to some of the world's challenges. As we celebrate the 150th anniversary of the periodic table, it seems reasonable to tip our hat to this, the first element on the table. […]
Good news for future tech: Exotic 'topological'...
on February 27, 2019 at 5:00 pm
In a major step forward for an area of research that earned the 2016 Nobel Prize in Physics, an international team has found that substances with exotic electronic behaviors called topological materials are in fact quite common, and include everyday elements such as arsenic and gold. The team created an online catalog to make it easy to design new topological materials using elements from the periodic table. […]
New periodic table of droplets could help solve...
on February 25, 2019 at 7:46 pm
Liquid droplets assume complex shapes and behave in different ways, each with a distinct resonance—like a drum head or a violin string—depending on the intricate interrelationship of the liquid, the solid it lands on and the gas surrounding it. […]
How scientists are piecing together the history...
on February 25, 2019 at 2:24 pm
In the solar system's early days, a first Earth is thought to have been pulverised by a planet that scientists call Theia. We don't know what it was made of or where it came from, only that it may have been the size of Mars. The powerful collision destroyed both planets so completely that scientists can only guess what they were like. […]
Physicists train the oscillatory neural network...
on February 22, 2019 at 12:49 pm
Physicists from Petrozavodsk State University have proposed a new method for oscillatory neural network to recognize simple images. Such networks with an adjustable synchronous state of individual neurons have, presumably, dynamics similar to neurons in the living brain. […]
When a defect might be beneficial
on February 19, 2019 at 1:40 pm
In the quest to design more efficient solar cells and light-emitting diodes (LEDs), a team of engineers has analyzed different types of defects in the semiconductor material that enables such devices to determine if and how they affect performance. […]
X-ray photoelectron spectroscopy of hydrogen and...
on February 12, 2019 at 11:47 am
For the first time scientists measured the vibrational structure of hydrogen and helium atoms by X-rays. The results disprove the misconception that it's impossible to obtain X-ray photoelectron spectroscopy (XPS) spectra of hydrogen and helium, the two lightest elements of the Periodic Table. This was thought to be the case due to low probabilities of electron ejection from these elements induced by X-rays. […]