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Mendeleev’s Periodic Table

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Last updated date: 17th Jul 2024
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An Introduction to Mendeleev Periodic Table

The chemical elements are shown in tabular form on the periodic table, commonly referred to as the periodic table of the (chemical) constituents. It is frequently employed in physics, chemistry, and related sciences and is regarded as a sign of chemistry. There are 118 elements listed in Mendeleev’s Periodic Table.


Out of them, 94 elements comprise indigenous elements, and 24 are made of synthetic materials. There were just 30 discovered elements in the year 1800. Scientists found it difficult to memorise the elements and their attributes as an increasing number of elements were discovered. They began compiling and classifying data related to the elements. It became common practice to group items into tabular categories based on their characteristics.


A periodic table is a tabular form that groups different elements into groups based on how they behave. Mendeleev's periodic table is a visual representation of the Mendeleev periodic law, which claims that the atomic numbers of chemical elements have a periodic influence on those elements' attributes. Thus, this article provides more detailed information on the table and its merits and demerits.


Define Mendeleev Periodic Law

According to Mendeleev's periodic law, an element's atomic weight is a periodical function of both its physical and chemical characteristics. Mendeleev postulated that the periodical physical and chemical characteristics of elements are based on their atomic weight in such a way that when they are arranged in a rising sequence of atomic weight, elements with comparable characteristics are replicated at periodic gaps of expanding atomic weight.


Mendeleev’s Periodic Table

Russian scientist Dmitri Ivanovich Mendeléev made the most significant contribution to the initial creation of the periodic table. Mendeleev's periodic table was the finest fundamental of several periodic tables that were created.


Once the Newlands Octave Law was rejected in 1869, Mendeleev's Periodic Table entered the scene. In Mendeleev's periodic table, elements were grouped according to their basic characteristic, atomic mass, and molecular characteristics. Just 63 elements were discovered at the time of Mendeleev's research. Mendeleev discovered a periodic relationship between the characteristics of elements and atomic mass after researching the characteristics of each element.


He organised the elements so that they fell within the similar vertical columns of the periodic table and had comparable qualities. These vertical columns were known as Groups by Mendeleev, while the next horizontal rows were known as Series. The accomplishment of Mendeleev can be attributed to his idea of classifying elements depending on the resemblance in their empirical formulas and the characteristics of the compounds they can produce. This caused him to sometimes deviate from the order in which atomic weights group alongside elements with comparable characteristics.


For instance, due to the similarity in their characteristics, fluorine, chlorine, and iodine, all of which have lower atomic weights than tellurium, were all assigned to Group 7 together with iodine.


Mendeleev Periodic Table


Mendeleev Periodic Table


Mendeleev‘s Modern Periodic Table

The prolonged format of the periodic table is the current version that is commonly utilised around the world. The vertical columns and horizontal rows in this type of periodic table are referred to as the groups and the periods, respectively.


Element groupings are made up of atoms with comparable outer shell electronic configurations. The groups' former names were IA,...VIIIA, VIII, IB,...VIIB, and 0. However, today they go by the numbers 1, 2, 3...18. Periods are represented by the 7 horizontal rows in the current periodic table. The period of the element is determined by the fundamental quantum number n.


Among the 4 quantum numbers (n, l, m, and s), one is the principal quantum number (n). It provides information about the fundamental electron shell. For instance, if n=3, it means that the primary shell is number 3.


Merits of Mendeleev’s Periodic Table

  • Mendeleev's periodic table had gaps since not all elements were discovered at the time; so, if a novel element is found, it can be added to a new group without affecting the already existing groups.

  • He was also able to forecast certain of the unknown elements' properties using the periodic law.


Demerits of Mendeleev’s Periodic Table

  • Mendeleev searched the periodic table for hydrogen but couldn't locate it.

  • While migrating from one element to the next, the rise in atomic mass was inconsistent. Therefore, it was unpredictable how many elements were still to be identified.

  • Eventually, isotopes of some elements were discovered that went against Mendeleev's periodic law.


Interesting Facts

  • The Mendeleev periodic law, regarded as a significant finding in the late 19th century, was described by the finding of the atomic number and ground-breaking research in quantum mechanics in the early 20th century, which revealed the underlying atomic structure.

  • The characteristics of an unidentified element that must fit beneath aluminium in the table were predicted by Mendeleev.

  • The properties of that element, known as gallium, were determined to be rather closer to Mendeleev's forecasts when it was identified in 1875. Mendeleev's periodic table was further validated by the eventual discovery of two additional anticipated elements.


Key Features to Remember

  • In 1869, Mendeleev introduced his periodic table. His organisation of chemical elements was focused on atomic mass.

  • Mendeleev's periodic table made it feasible to anticipate characteristics of elements which had yet to be identified.

  • The vertical columns were known as Groups by Mendeleev, while the next horizontal rows were known as Series.

  • Every version of Principles of Chemistry was revised by Mendeleev, who included all new scientific information, especially evidence for the periodic law, and re-analysed any obstacles to its validation (radioactivity, and rare-earth, inert gases elements).

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FAQs on Mendeleev’s Periodic Table

1. Which chemical element has Mendeleev's name?

Mendelevium was the chemical element named after Mendeleev, which was discovered in 1955 by Albert Ghiorso and his colleagues.

2. How did the missing elements named by Mendeleev?

With relative atomic weights of 100, 72, 68, and 44, Mendeleev gave them the names eka-manganese, eka-silicon, eka-aluminium, and eka-boron.

3. How many elements were predicted by Mendeleev?

Three chemical elements were predicted by Mendeleev. Depending on patterns he had noticed in his periodic table, he anticipated the existence of these chemical elements. He correctly identified the elements gallium, germanium, and scandium.