What did Mendeleev discover?

Periodic table
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Dmitri Mendeleev/Inventions

On 17 February 1869, Russian chemist Dmitri Mendeleev jotted down the symbols for the chemical elements, putting them in order according to their atomic weights and inventing the periodic table.

What is Mendeleev’s periodic law class 10?

Mendeleev’s periodic law states that; The physical and chemical properties of elements are a periodic function of their atomic weights.

What did Mendeleev organize the periodic table by?

increasing relative atomic mass
Features of Mendeleev’s tables Mendeleev arranged the elements in order of increasing relative atomic mass . When he did this he noted that the chemical properties of the elements and their compounds showed a periodic trend .

How many elements did Mendeleev discover?

70 elements
His newly formulated law was announced before the Russian Chemical Society in March 1869 with the statement “elements arranged according to the value of their atomic weights present a clear periodicity of properties.” Mendeleev’s law allowed him to build up a systematic table of all the 70 elements then known.

What was wrong with Mendeleev’s periodic table?

Another problem Mendeleev encountered was that sometimes the next heaviest element in his list did not fit the properties of the next available place on the table. He would skip places on the table, leaving holes, in order to put the element in a group with elements with similar properties.

Why was Mendeleev’s periodic table widely accepted?

Mendeleev’s table became widely accepted, primarily because he predicted the characteristics and placement of elements which were yet to be discovered. One of the major developments that allowed for what became known as the periodic table was the idea of atomic mass, which is attributed to John Dalton.

What are the disadvantages of Mendeleev’s periodic table?

Demerits of Mendeleev Periodic Table

  • He was unable to locate hydrogen in the periodic table.
  • Increase in atomic mass was not regular while moving from one element to another.
  • Later on, isotopes of elements were found which violated Mendeleev’s periodic law.

Why was Mendeleev’s table accepted and Newland’s wasn t?

One of the reasons Newland’s table was not accepted was that he had many more dissimilar elements in a column whereas Mendeleev left gaps for undiscovered elements. Mendeleev also predicted the properties of missing elements, which were later discovered, fitting the gaps and matching the predicted properties.

Can you now say why Mendeleev?

Mendeleev developed a Periodic Table of elements wherein the elements were arranged on the basis of their atomic mass and also on the similarity on chemical properties. On this basis he formulated a Periodic Law, which states that ‘the properties of elements are the periodic function of their atomic masses’.

What made Mendeleev’s periodic table unique?

One of the unique aspects of Mendeleev’s table was the gaps he left. In these places he not only predicted there were as-yet-undiscovered elements, but he predicted their atomic weights and their characteristics.

Why was Newlands table not accepted?

Newlands’ table showed a repeating or periodic pattern of properties , but this pattern eventually broke down. By ordering strictly according to atomic mass, Newlands was forced to put some elements into groups which did not match their chemical properties. As a result, his table was not accepted by other scientists.