Mendeleev Periodic Table (original) (raw)

Last Updated : 23 Jul, 2025

Mendeleev's Periodic Table was the first bold attempt to arrange all the known elements in a proper manner. This table was based on the principle of Mendeleev’s Periodic Law and was a significant step made in the direction of arranging all the known elements.

According to Mendeleev, the characteristics of elements are a periodic function of their atomic masses and thus he arranged all the known elements of that time in increasing order of their atomic mass in the form of a table called Mendeleev's Periodic Table.

Let's learn more about Mendeleev’s Periodic Law and his periodic table in detail in this article.

What is Mendeleev’s Periodic Law?

People from the very start tried to arrange known elements in a proper manner to study their properties in a more effective manner. Various people have come up with various ideas to arrange the elements such as the New Land law of Octaves, Dobereiners Triads, etc. But the most significant step in this direction was made by the famous Russian scientist Dmitri I. Mendeleev in 1869. He based his theory on the basis that the properties of chemical elements are the function of their atomic mass. According to him, " The physical and chemical properties of the elements are the periodic function of their atomic weights." This law is called Mendeleev’s Periodic Law.

Who is called the Father of Periodic Table?

The famous Russian scientist Dmitri Ivanovich Mendeleev also called Mendeleev is called the Father of the Periodic Table. He was born on 8 February 1834 in the small town of Tobolsk in Siberia. He was an alumnus University of St. Petersburg. and received and received his Master’s degree in chemistry in 1856 and his doctoral degree in 1865.

Introduction to Mendeleev Periodic Table

In 1869, Dmitri Mendeleev came up with a periodic table of chemical elements based on the properties that appeared in the elements. He placed the elements from lightest to heaviest. Before Mendeleev's Periodic Table, Dobereiner's triads and Newland's Law of Octaves were mostly considered for the classification of elements in the form of tables.

**Mendeleev's Periodic Table came into the picture after the rejection of Newland's Law of Octaves. In Mendeleev's Periodic Table, elements are distributed according to their atomic masses, fundamental property, and chemical properties.

Mendeleev's Periodic Law states that "The properties of elements are the periodic function of their atomic masses."

At the time when Mendeleev formulated this periodic table, only 63 chemical elements had been discovered. After observing all the properties of the elements, Mendeleev concluded that the properties of the elements periodically related to their atomic masses. Other than atomic masses, Mendeleev also used chemical properties to categorize. Formulae of hydrides and oxides of the elements were one of the primary criteria for categorization. He arranged the elements in the periodic table such that all the elements with similar properties would fall in the same vertical columns of the periodic table. He named the vertical columns "**groups" and the horizontal rows "**periods".

Mendeleev recognized the significance of periodicity. He used a broader range of physical and chemical properties in order to classify the chemical elements. Particularly, he relied on the similarities in the given empirical formulas and properties of the compounds such as oxides and hydrides formed by the elements.

Mendeleev noticed that some of the elements didn't fit according to the periodic law if the order of atomic masses was followed strictly. He thus ignored the order of atomic masses, assuming that the atomic measurements might be incorrect, and placed the elements with similar properties together. For example, the atomic mass of Tellurium is more than that of Iodine. Yet, he placed Iodine with Group VII and Tellurium in Group VI. This was because Iodine has more similar properties to Chlorine, Fluorine, and Bromine. At the same time, keeping his primary aim of arranging the elements of similar properties in the same group, he proposed that some of the elements were still undiscovered and, therefore, left several gaps in the table.

**Merits of Mendeleev's Periodic Table

Merits of Mendeleev's Periodic Table are,

• It was one of the first periodic tables that successfully accommodated all known elements at that time.
• It gave the periodic law based on which the modern periodic law was formed.
• The table had gaps for undiscovered elements, which proved to be beneficial in the discovery of new elements. The periodic table was not disturbed in any way.
• Mendeleev's Periodic Table in 1869 had only seven groups, but Sir William Ramsay suspected new elements belonging to a hitherto unknown eighth group.
• Ramsey and Rayleigh discovered noble gases in 1895. These noble gases were added to Mendeleev's Periodic Table as a separate group.

**Demerits of Mendeleev's Periodic Table

Demerits of Mendeleev's Periodic Table are,

• Hydrogen, the first element to begin with didn't have a definitive place on the table. It was placed differently from the rest of the elements.
• Isotopes are variants of a particular element that have the same atomic number but differ in atomic mass. These isotopes violated Mendeleev's Periodic Table as they couldn't be placed.
• The increase in the atomic mass of the elements is irregular and not in a fixed pattern. Thus, it was not possible to exactly determine how many elements were yet to be discovered.

Predictions of Mendeleev's Periodic Table

Mendeleev has made various predictions on the elements that are not known till that time on the basis of the atomic mass of the other elements present.

• Mendeleev predicted several elements after observing his periodic table. He estimated that some unfilled spots would be similar to elements existing in the given group.
• He named some elements as (eka)-(similar element), where Eka means 'one' in Sanskrit.
• Mendeleev predicted eka-boron (Eb), eka-aluminium (Ea), eka-manganese (Em), and eka-silicon (Es).
• These elements were later discovered to be Scandium, Gallium, Technetium, and Germanium respectively.
• Mendeleev also predicted an element between Thorium and Uranium amongst others.

Mendeleev's Predictions and Actual Properties on Discovery:

To conclude, in his time, Dmitri Mendeleev made a very insightful Periodic Table based on the Atomic Masses of Elements. It was the foundation of the Modern Periodic Table and successfully predicted several unknown elements of that time.

Difference between Mendeleev's Periodic Table and Modern Periodic Table

The difference between Mendeleev's Periodic Table and Modern Periodic Table are discussed below in the table,

**Read More,

• Periodic Classification of Elements
• History of Periodic Table
• Merits of the Modern Periodic Table