What is a description of the periodic table?

Answer 1

In 1869 Russian chemist Dimitri Mendeleev formulated the periodic law, which stated that properties of elements recurred in a pattern. Based on this, he also helped develop the Periodic Table, predicting the discovery of multiple elements rather accurately.

Answer 2

The periodic table of the chemical elements is a tabular method of displaying the chemical elements. Although precursors to this table exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869. Mendeleev intended the table to illustrate recurring ("periodic") trends in the properties of the elements. The layout of the table has been refined and extended over time, as new elements have been discovered, and new theoretical models have been developed to explain chemical behavior.

Answer 3

Since antiquity, around the 400s BC, in ancient Greece,they have used the words "element" and "atom" to describe the differences between different parts of the material and to designate the smallest parts that make up matter.

In the eighteenth century, the great French chemist Antoine Lavoiser, in his " 'Traité élémentaire de Chimie (Elementary Treatise of Chemistry), published in 1789, divided the 33 elements known in his time, in four groups according to chemical properties: gases, non-metals, metals, and earth.

In the nineteenth century, in 1869 German scientist Johann Döbereiner noted that similar elements have similar atomic masses. He eleborat the so-called Law of triads which consist of dividing the items into groups of three similar elements, the middle element properties being deduced from the properties of the most difficult element and the easiest item.

Examples of triads in this table: lithium, sodium and potassium, sulfur, selenium and tellurium and chlorine, bromine and iod.Cercetătorul French Chancourtois made a cylindrical table of elements to show a periodic recurrence properties of chemical elements. In 1865, another researcher who attempted classification of items was Englishman John Newlands, professor in the School of Medicine in London.

He placed the items in a table consists of 7 columns in order of increasing Atomic Mass. He pointed out that elements with similar properties occur at intervals of 8 elements and eleborat so-called Law of octaves.

Other contributions to the classification of chemical elements, were also brought by English scientist William Olding, in 1864 and German scientist Julius Lothar Meyer in 1868.

W. Olding has made a table very similar to that made later by Mendeleev. The groups are arranged horizontally and the elements are arranged in order of atomic mass. In the tables were left blanks for undiscovered elements.

German chemist Julius Lothar Meyer made a table of chemical elements in 1864, then a second version in 1868, where the elements were arranged in order of atomic mass. Mayer published his work much later than Mendeleev, so could not prevail in this area. It seems that the two chemists, Meyer and Mendeleev discovered the periodic system of elements simultaneously.

He who is widely accepted as the discoverer of the periodic system of elements was modern Russian chemist Dmitri Ivanovich Mendeleev. The final version of the system periodically in 1871 has left spaces suggesting that other chemical elements will be discovered later. Element 101 was named after Dmitri Ivanovich Mendeleev (1834-1907), who discovered the "Periodic System" arranged in tabular form and continuously improved between 1868 and 1871.

Answer 4

The periodic table of elements was created by a Russian chemist Dimitri Ivanovich Mendeleïev in 1869. He noticed that some properties varied with the atomic mass. He decided to classify them in this order.

In 1913, the classification evoluted, and the elements were classified according to their atomic number (the number of protons).

Answer 5

A History of the Periodic Table

The History of the Periodic table has been one of constant evolution and development. Arguably beginning with Antoine Lavoisier, who wrote the first extensive list of some 33 elements in 1789, the Periodic Table's history then stretches all the way to the 1940s with Glenn Seaborg's contributions. It has even been estimated that there are still a few more elements to be discovered and added to the table.

The actual idea of elements which the world consists of was thought of by Aristotle around 330 BC. He came up with the theory that there were four elements or "roots" as they were known: Earth, Air, Water and Fire. While the idea of there being a limited number of chemical elements from which everything in the world is composed of is a more modern idea, people from as far back as ancient times have been aware of certain, easier to mine, chemical elements such as gold, silver and copper.

The first chemical element to be discovered and recorded was phosphorus, the finding of which was entirely coincidental. It was in pursuit of the "philosopher's stone" - a mythical object - that the bankrupt German merchant stumbled across a glowing substance when distilling urine in 1649. He kept his discovery secret until it was rediscovered in 1680 and made public by Robert Boyle. Boyle decided that an element was a subject that cannot be broken down into a simpler form by a chemical reaction. This tangible definition remained official for almost 300 years.

Lavoisier's list in 1789 was the next major landmark in the Table's development. Although the list classified elements into two categories (metals and non-metals), it included light which he believed to be a material substance.

The Swedish chemist Jöns Jakob Berzelius then created a table of atomic weights, introducing letters to symbolise elements, as well as identifying a few of his own, including silicon and cerium. Much of his work was done in around 1828.

Also around this time, Johann Döbereiner, began to classify the known elements further, realising that some of them could be placed in groups of 3 which had related properties. He called these groups "triads", an example being lithium, sodium and potassium.

Later, in 1865, the Englishman John Newlands put the 56 elements discovered at the time into 11 groups, again based on similar physical properties. He suggested the "law of octaves", and was a forerunner to the notion of periods.

Shortly after, a Siberian-born chemist by the name of Dmitri Mendeleev, made another considerable change to the Periodic Table. He produced a table based on atomic weights, although arranged them "periodically", placing elements with similar properties underneath each other. He allowed space for elements that were unknown at the time and their predicted properties. He re-arrange the order of elements if their properties required it, eg, tellurium is heavier than iodine but comes before it in the Periodic Table.

William Ramsay discovered the noble gases towards the end of the 19th century. He removed oxygen, nitrogen, water and carbon dioxide from a sample of air, which left him with a gas 19 times heavier than hydrogen, very unreactive and with an unknown emission spectrum. He named it Argon. Going on to discover helium, krypton, xenon and neon he revealed a new group of elements in the Periodic Table and won a Nobel Prize in 1904.

In 1914, Henry Moseley altered the 'Periodic Law' so that the properties of the elements varied periodically with their atomic numbers.

The last major contribution to the periodic table was Glenn Seaborg's synthesising of the transuranic elements (the elements after uranium in the periodic table) in 1940.

Answer 6

The periodic table consist of metals, nonmetals, and gas elements.

Answer 7

First the elements had to be discovered. Then their properties must be figured out. It all evolved until the current periodic table, which is still being updated.

Answer 8

See the link below for details.