Check sibling questions

(i) Why do we classify elements?

(ii) What are the two criteria used in the development of Modern Periodic Table?




We classify the elements so as to ensure a systematic and simplified study . By classification, we can study the properties of elements and their compounds properly.


In the modern periodic table, elements were classified based on their 

  • atomic number 
  • chemical properties


Position of Metals Non-Metals and Metalloids in The Periodic Table - Teachoo.jpg

Metals are placed towards the left of the periodic table, non metals towards the right and metalloids are present in the middle in a zigzag fashion.


In the modern periodic table, elements are classified based on their atomic number and not atomic masses .  

Although isotopes have different atomic masses, they have the same atomic number and similar chemical properties. 

So, they should be placed in the same slot .

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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 13 years and a teacher from the past 17 years. He teaches Science, Economics, Accounting and English at Teachoo