ORIGIN OF THE ELEMENTS

Greetings,
I am new to the forum and not really versed in element details.
Just wanted to know if scientists discover the elements or make them as required?
Do you know what to look for when searching for a new element and how do you
know what to look for?

Thank you very much.

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Some elements were known from

Some elements were known from antiquity but not recognized as such. Ancient philosophers used the term element to refer to presumed basic constituents of matter [earth, air, fire, water]. The concept of chemical elements as basic constituents of all known substances evolved in the late eighteenth century and chemists then set about trying to resolve common substances into their elements. When Sir Humphrey Davy was able to break down lye and potash into new metals, he discovered the elements sodium and potassium. It was earlier shown that alum (potassium aluminate) combined potassium compounds with alumina (aluminum hydroxide) and Davy attempted to isolate the pure metal without success. Because nitrogen dioxide dissolves in water to produce nitric acid and sulfur trioxide in water gives sulfuric acid, Lavoisier taught that all acids contain oxygen; therefore, he concluded that chlorine which combines with hydrogen to give a gas that dissolves in water to give hydrochloric acid was a compound of oxygen. It took some time before all chemists accepted the idea that chlorine itself was an element.

By and large the early search for elements was hit and miss. This changed in the 1860s when Dmitrij Mendeleev produced a periodic chart of the elements as a teaching aid for his first year chemistry students. Mendeleev showed that the chemical properties of elements changed with the atomic weight and that similar properties recurred after a period (the periodic "law"). To make his idea work out, Mendeleev had to assume that each element was assigned an atomic number and that some atomic numbers belonged to yet undiscovered elements.

From that time forward, chemists had a pretty clear idea of how many elements there were and what properties would be found. Mendeleev himself predicted five of these in his 1869 and 1870 tables, and three of these elements, eka-boron, eka-aluminium, and eka-silicon were found shortly thereafter with much the properties predicted by Mendeleev. Eka-manganese and dvi-manganese were not found, but chemists were now confident that such elements existed. In 1925 respected German researchers announced the discovery of eka-manganese (masurium) and dvi-manganese (rhenium). The first discovery was not reproduced by other labs and discounted, but the second was confirmed.

Before that discovery, it was shown that uranium (which was an eighteenth-century discovery) was naturally radioactive, and Marie Curie noting that pitchblend (uranium ore) was more highly radioactive than pure uranium reasoned that there was a rare element even more radioactive in pitchblend. She and her husband Pierre managed to isolate two elements radium with chemical properties like barium and calcium (belonging then to Group 2) and polonium with properties much like tellurium (group 16). Radioactivity demonstrated that atoms were not, as Dalton thought, indivisible particles but were made up on smaller parts. Henry Mosley's demonstration that x-ray diffraction of elements corresponded to the number of electrons in the outer shell and so to the atomic number showed that the atomic number was not just a bookkeeping device as Mendeleev imagined, but the actual justification for the periodic arrangement of chemical properties caused by the configuration of available electrons balancing the number of protons in the nucleus. With the realization that the atom was composed of a nucleus with protons and neutrons and that radioactive nuclei were releasing high-speed particles, it became possible to aim these particles into other nuclei and create new elements. In 1937, Italian scientists aimed these particles at a molybdenum target (element 42) and produced Mendeleev's element 43, technetium, which obligingly had chemical properties much like its period 7 analog, manganese. By 1940, American scientists aimed particle beams into a uranium target and created neptunium, element 93 and later plutonium (94). Soon they were able to create further transuranic elements. The discovery of francium (87) in 1939 and creation of promethium (66) in 1945 filled in the periodic chart and any further elements have to be created in the lab by using ever more powerful accelerators to smash nuclei together.

These new synthetic elements are now known upto 118, but only by very few atoms which last only milliseconds before decaying. The next element to be discovered should be 119 or 120. 119 will behave like cesium or francium (francium is known by microchemistry, but no one has ever seen visible amounts of the very rare element) 120 should behave like calcium, strontium, barium, and radium. There is a good chance that 120 will be confirmed before 119 because even numbered nuclei are apparently easier to form than odd-numbered nuclei.

I hope this answers your question. Originally, chemists discovered elements by chance; after the periodic law they were able to deliberately search for elements of an approximate weight and predictable chemical properties. After the discovery of sub-atomic particles, chemists were able to synthesize elements heavier than uranium and have done so up to 118. These are now the only elements that remain to be discovered, those in period seven (119 to 168).

Yes and thank you for the

Yes and thank you for the info and back-ground.

I was asking mainly also as to the chances that these elements would just come
together by "accident" and not by Intelligent Design-me being a religious person.
It seems to me that the right number of electrons ending up in the proper shell is
no "chance happening".

Also are you saying that the number of elements are a set number and how would
you know?

Thank You

thanks www.evdepazar.com

thanks

www.evdepazar.com

Hi, You have really provided

Hi,
You have really provided a helpful discussion on origin of elements of chemistry
,thank you very much for it.
-----------------------------
Debra Fine

Martin17 thanks for this post

Martin17 thanks for this post i'm new too in this forum an i fownd very interesting informations thanks again :)
http://www.belvini.de/lexikon/Champagner.html

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