NCERT in ‘rationalisation’ move drops periodic table chapter from Class X book

Subject : Science and technology

Section: General Science

Concept :

The chapter on ‘Classification in Elements and Periodicity in Properties’ in NCERT’s Class 11 Chemistry textbook begins with these words of American chemist Glenn T Seaborg.
Yet, a full chapter, which introduces students to the topic, has been removed from NCERT’s Class 10 Science textbook as part of the council’s “rationalisation” exercise. The Class 11 chapter on the topic, however, remains part of the syllabus.

Periodic Table of elements

The periodic table is an organisation of all known elements in order of increasing atomic number and recurring chemical properties.
They are organised in a tabular format, with a row representing an era and a column representing a group.
Elements are ordered in increasing atomic number order from left to right and top to bottom. Elements of the same group will therefore have the same valence electron configuration and, as a result, identical chemical characteristics.
Elements in the same period, on the other hand, will have an increasing order of valence electrons.
As a result, as the atom’s energy level rises, so does the number of energy sub-levels per energy level.
The first 94 elements of the periodic table occur naturally, but the remaining elements from 95 to 118 have only been created in laboratories or nuclear reactors.
The contemporary periodic table, which we presently use, is a revised and enhanced version of certain models proposed by scientists in the nineteenth and twentieth centuries.
Dimitri Mendeleev proposed his periodic table based on the discoveries of previous scientists such as John Newlands and Antoine-Laurent de Lavoisier. Mendeleev, on the other hand, is awarded sole credit for developing the periodic table.

Why Arrange Elements in a Table?

The contemporary periodic table of chemical elements is as familiar as a map of the earth, yet it was not always so evident.
Dmitri Mendeleev, the author of the periodic table, began collecting and organising known properties of elements while travelling by train in 1869, as if he were playing a game. He discovered groups of elements with similar features, but he also noticed that there were many exceptions to the emerging patterns.
There were many critics, and it took years for Mendeleev’s patterns to be accepted internationally, but after freshly discovered elements matched those predicted by Mendeleev, his patterns could not be disregarded.
Furthermore, some of the “fudged” attributes were later recalculated and found to be substantially closer to his predictions.
Instead of giving up, he experimented with changing the measured property values to better fit the patterns! In order for the patterns in his “game” to operate, he anticipated that certain elements needed exist that did not exist at the time.

Who Created The Periodic Table?

According to the Royal Society of Chemistry, Dmitri Mendeleev, a Russian chemist and inventor, is regarded as the “father” of the periodic table (opens in new tab).
Periodic Table: Mendeleev was a prominent lecturer at a university in St. Petersburg, Russia, in the 1860s. Mendeleev opted to produce one because there were no new organic chemistry textbooks in Russian at the time.