GK SCIENTIST

General Knowledge One Stop Source
Menu
  • Home
  • Social Science
    • History
    • Political Science
    • Geography
  • Science
    • Physics
    • Chemistry
    • Biology
  • Chemistry Notes
  • Mathematics
  • Computer
  • Tutorial MySQL
  • Tutorial Python
  • Java Tutorial
  • English Grammar
  • English Essay
  • Indian Anthropology
  • Philosophy
  • Solved Paper
  • UPSC
  • Current Content
    • Current Affairs
    • RSTV News
    • Yojana and Kurukshetra Gist
  • Donate
  • Contact Us

If you are interested in advertising to our audience, submit the advertising enquiry form.

Advertising Enquiry
Science

Periodic Law of Mendeleev

Gk Scientist December 29, 2020 No Comments
Tweet WhatsApp Telegram

Periodic Law of Mendeleev:

Newlands concept of arrangement of elements was further developed to a large extent by Mendeleev (1869), a Russian chemist. Mendeleev pointed out that when the elements are arranged in the order of their increasing atomic weights, those which are chemically similar recur at regular intervals. This relation between the elements was termed the Periodic Law, which he stated as given below-

The properties of elements are periodic functions of their atomic weights.

On the basis of the periodic law, Mendeleev arranged the elements in the form of a table, known as Mendeleev’s Periodic Table.

In order to lay more stress on similarities in properties of elements rather than rigidly following the increasing order of their atomic weights, Mendeleev had to deviate from the periodic law. While framing his table, he kept some vacant places and predicted the existence of yet unknown elements to fill up these gaps. He could even foretell the properties of these elements by studying the properties of neighbouring elements. Such elements were discovered later and were found to have almost the same properties as had been predicted by Mendeleev.

The latest form of Mendeleev periodic table also includes those elements which were not known when the original table was framed. In this table:

  • The vertical columns are known as groups. There are nine groups in all, numbered from 0 (zero) to VIII. Zero group consists of inert gases which were discovered after Mendeleev had published his periodic table. The elements in any given group are of very similar chemical behaviour. The nine groups in the periodic table are regarded as-
    1. Seven regular groups (Group I to Group VII)- Normal groups.
    2. One transitional group (Group VIII)- A group of transitional elements.
    3. One zero group of inert gases.
  • The groups I to VII are subdivided into two subgroups A and B. Group 0 is either placed before the group I or it is made the sub-group B of group VIII.
  • The horizontal rows are known as periods. These are seven in number. The number of elements present in each period is shown in the following table.
Period1234567
No. of Elements288181832Incomplete
6 naturally occurring + the rest (discovered by nuclear reactions)

The 14 are rare earth elements beginning after Lanthanum (Atomic Number 57) are known as Lanthanides. These elements resemble in properties. The elements, which begin after Actinium (Atomic Number 89) in the 7th period are referred to as Actinides.

Mendeleev‘s periodic table proved itself of greatest value regarding the advancement in the study of chemical elements. It had, however, certain anomalies which could not be explained. Some of the anomalies are-

  • Isotopes of the elements having different atomic weights could not be provided separate places in the periodic table. If we attempt to arrange them according to their atomic weights in the normal manner, the periodic character of the table would be upset.
  • As exact atomic weights became known, it was found that some elements with higher atomic weights preceded those with lower atomic weights. For example- Argon (Atomic Weight = 39.94, Group 0) comes before Potassium (Atomic Weight = 39.10, Group I); Tellurium (Atomic Weight = 127.6, Group VI) comes before Iodine (Atomic Weight = 126.9, Group VII).

It appeared that it was not the atomic weight but some other fundamental property of the elements which could give a better understanding of the periodicity in the properties of the elements. This property was found to be the atomic number.

Charles Law (Volume-Temperature Relationship for a Gas)
  • Lamarckism And Neo-Lamarckism
  • Darwinism or Theory of Natural Selection
  • Constituents of Food: Carbohydrates, Proteins, Fats & Vitamins
  • Asexual Reproduction- Types, Characteristics And Significance
  • Vegetative Propagation: Natural & Artificial Methods
  • Parthenogenesis: Types And Significance
  • Pollination: Types and Its Importance
  • Chlorophyta- Green Algae
  • Rhodophyta- Red Algae
  • Bryophytes- Characteristics And Economic Importance
  • Essential and Non-essential Parts of the Flowers
  • Plant Growth and Development
Prev Article
Next Article

Related Articles

Importance of Coordination Compounds
Importance of Coordination Compounds: The coordination compounds constitute the minerals, …
Gk Scientist July 18, 2021 Science

Importance of Coordination Compounds

Applications of Ion Exchange Chromatography
Applications of Ion Exchange Chromatography: Ion exchange chromatography has proved …
Gk Scientist January 17, 2022 Science

Applications of Ion Exchange Chromatography

Download NCERT Biology Books For Competitive Exam
NCERT Biology Books For Competitive Exams- Both In English / …
Gk Scientist September 10, 2020 Science

Download NCERT Biology Books For Competitive Exam

Osmoregulation of Kidneys
What is meant by the term Osmoregulation? It is the …
Gk Scientist October 26, 2020 Biology Questions, Science

Osmoregulation of Kidneys

Elasticity and Hooke’s Law
Elasticity and Hooke’s Law: Elasticity: When an external force acts …
Gk Scientist January 7, 2021 Science

Elasticity and Hooke’s Law

General Characters of Gymnosperms And Angiosperms
Gymnosperms And Angiosperms: General Characters of Gymnosperms: The ‘Gymno’ means …
Gk Scientist November 28, 2020 Science

General Characters of Gymnosperms And Angiosperms

Steady State and Homeostasis
Steady State and Homeostasis: Steady State refers to a system …
Gk Scientist January 31, 2021 Science

Steady State and Homeostasis

Resistance and Resistivity of a Conductor
Resistance and Resistivity: What is Resistance? Resistance of the conductor …
Gk Scientist July 26, 2021 Science

Resistance and Resistivity of a Conductor

Leave a Reply Cancel Reply

Search




  • Popular
  • Recent




GK SCIENTIST

General Knowledge One Stop Source

Information

  • About Us
  • Terms and Condition, Disclaimer
  • Contact Us

Android Apps

  • IAS App For English Medium Students
  • IAS Basics App For English Medium Students
  • IAS Hindi App For Hindi Medium Students
DMCA.com Protection Status

Popular Tags

Biology (33) Biology Questions (88) Chemistry (57) Computer (215) Current Affairs (4) Current Content (0) Economy (10) English Essay (172) English Grammar (75) English Literature (10) Geography (83) History (259) Indian Anthropology (11) Indian Polity (14) JKAS Mains Question Papers (17) Mathematics (68) Moral Science (7) NCERT & Other Boards Books (25) Philosophy (114) Physics (89) Political Science (132) RS TV News (33) Science (553) Social Anthropology (7) Social Science (17) Solved Paper (47) UPSC (7) UPSC Mains Question Papers (26)

Downloads

  • NCERT Books
  • Old NCERT Books
  • NIOS Books For IAS, SSC, and State PSC Exam
  • Tamil Nadu Board Books: Important For UPSC, SSC, and State PSC Exam
  • Modern Indian and World History Notes For IAS Exam
  • UPSC Topper 2013 Gaurav Agrawal Notes For IAS Preparation
  • UPSC IAS Prelims General Studies – Previous Year Papers
  • UPSC Mains Question Papers

Copyright © 2023 GK SCIENTIST
Theme by MyThemeShop.com& Hosted On Cloudways

Ad Blocker Detected

Our website is made possible by displaying online advertisements to our visitors. Please consider supporting us by disabling your ad blocker.

Refresh