His periodic was not in complete accordance with what he was classifying with i.e classification with respect to ascending Atomic Mass. here is an example: the atomic mass of the Ar is 39.9 and that of sodium is 39 but he placed Ar in the zero group and Na in the 1st group. this is one example. his Periodic Table had some more defects like this. this defect was observed when the true atomic masses were known. In his time the true atomic masses were not known. This was one of the reason for the failure of his periodic table.
To understand the concept of Periodic Table
In Mendeleev's periodic table, the elements were arranged in the increasing order of their atomic masses and repeating periodic properties.
Mendeleev predicted that properties of elements are periodic function of atomic mass. He demonstrated it by creating a table.
they changed the 3 new Elements.
elements
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Dmitri Mendeleev was a Russian chemist; he proposed the modern Periodic Table of elements in 1869.
Mendeleev's periodic table arranged elements by increasing atomic mass and grouped elements with similar properties together. Today's periodic table is similar, but it is arranged by increasing atomic number, which reflects the number of protons in an atom's nucleus. Both tables also show periodic trends in properties as you move across and down the table.
The properties of elements are the periodic function of their atomic numbers. REMOVAL OF DEFECTS OF MENDELEEV'S PERIODIC TABLE periodic table obtained on the basis of increasing atomic numbers has removed defects of Mendeleev's periodic table . 1) POSITION OF ISOTOPES : since the isotopes of the same elements have the same atomic number, they are given the same place in the table. 2) POSITION OF RARE EARTHS: These elements are separately placed at the bottom of table . similarly Acton elements ( which were discovered after Mendeleev ) are also placed at the bottom of the periodic table. 3) ANOMALOUS PAIRS. the arrangement according to the atomic number show that their placements are correct.
Actually, Dmitri Mendeleev formulated the periodic law and published his periodic table of elements in 1869. This table arranged elements by increasing atomic mass and grouped them based on similar properties, predicting the properties of missing elements. It was a significant contribution to the field of chemistry.
Mendeleev predicted the name "eka-aluminium" for the element that is now known as gallium. This naming convention was based on the positions of the elements in his periodic table.
Dmitri Mendeleev was a Russian chemist who proposed the Periodic Law. He published the first periodic table of the chemical elements in 1869, based on the increasing atomic masses of the different elements.