perodic table detailed notes part-2

Class 10th Science Ch-5 Chapter Detailed Notes Part-2 {Periodic Table & it’s Classification}

perodic table detailed notes part-2
perodic table detailed notes part-2

Class 10th Science Ch-5 Chapter Detailed Notes Part-2 {Periodic Table & its Classification}, As you understand from its title that this is the 2nd and the Last part of our series. If you are directly landed on this page then you can check out the Part-1 of this Series.

In this part of our detailed notes series, we will end this chapter. We are going to discuss the ModernPerodic table, Trends of the modern periodic table. And how we place the elements in the Modern periodic table. how the properties of the different elements change in the Periods and Groups of the Modern periodic table.

Here if the Table of Content, That will help you in the easy navigation through the website.

Modern Periodic Table:-

In 1913, Henry Mosely showed that the atomic number of an element is a more fundamental property than its Atomic mass.

Mosely proposes the new Modern Periodic law that was:- “The Properties of the elements are the periodic function of their atomic number”.

If you are looking for something else related to this chapter like- NCERT Solutions, Exemplar Solutions, Practice Paper or Solved Question Answers, then you can go and check to them as well.

Let’s move Further

Why Atomic number is considered more important than their Atomic Masses?

Properties of the different elements are depending on their electronic configuration, not on their atomic mass.

Also, the problem of the Isotopes was solved because in the modern periodic table the elements are placed according to their Atomic Number.

In the modern periodic table, There are 7 Periods and 18 groups. Group 1 elements are known as the Alkali element.

2. Group 2 elements are known as the earth-alkali elements.

3. Group 3 to 12 elements are known as the transition elements.

4. Group 13th is known as Boron Family. And group 14th is known as the Carbon Family.

5. Group 15th is known as Pnictogens. And Group 16 is known as Oxygen family or chalcogens.

6. Group 17 elements are known as Halogens and Group 18 elements are known as Noble Gases.

Position of the Elements in the Modern Periodic Table:-

There are 18 groups and the 7 periods and each and every period starts with the new shell.

Long Form of Periodic Table:- Class 10th Science Ch-5 Chapter Detailed Notes Part-2

Left Part (Group 1 and group 2 elements) also known as S-block, Middle part (Group 3- 12) also known as D and F Blocks, and Right part (Group 13-18) Known as P-block elements.

There are further subparts of the Middle part:- Transition and Inner Transition Elements.

Transition Elements:- First Transition Series:- Sc (21) to Zn (30)

Second Transition Series:- Y (39) to Cd (48)

Third Transition Series:- La (57) and Hf (72) to Hg (180)

Forth Transition Series:- Ac (89) and Rf (104) to Rg(111)

Inner Transition Elements;- Lanthanides (14 elements), Actinides (14 elements).


The first Period has 2 elements and it is known as the shortest period.

2nd and the 3rd period has the 8 elements and it is known as the short periods.

4th and the 5th period have the 18 elements and these periods are known as the long period.

6th and the 7th period has the 32 elements and it is known as a very long period.

** S + P block elements collectively known as the Representative elements.

What are the advantages of the classification of elements?

The classifications of the elements are compulsory So that we can study all the elements in a systematic manner.

The Classification of the elements in a periodic table helps in correlating the properties of the elements.

This also helps in the study of the different compounds that are formed by different elements.

What is the basic difference between Mendeleev’s periodic table and the Modern Periodic table?


Mendeleev’s periodic tableModern Periodic Table
His Table was based on the Atomic Weight.This Periodic table is based on the Atomic Number.
There were 8 groups and 12 periods in his table.There are 18 groups and the 7 Periods in this Periodic table.
His table does not support the concepts of the atomic Structure.His table supports the concepts of the atomic Structure.
His table was not able to define the position for the Isotopes.There is no any defect in this table like Placement of Isotopes and Isobars.

** Trends in the Modern Periodic table:-

  1. Valency:- valency is the ability of the elements to combine with the other elements. The no. of electrons present in the outermost shell is considered as the valency of the element.
    1. Valence Shell:- Outermost shell of an element is known as valence shell.
    2. Valence electrons:- Electrons that are present in the outermost shell of the element. Or no. of elements that are present in the valence shell.
    3. Valency:- if the electrons that will be present in the valence shell will be less than or equal to the 4 then the valency will be no. electrons present. But if the no. of electrons present in the outermost shell will be higher than 4 then it will be subtracted from 8.

2. Atomic Size:- The Distance of Nucleus of the atom from its outermost shell is known as Atomic Size. This is also known as atomic Radius. The distance between the nucleus of the atom and its outermost shell is known as Atomic Size.

How the Atomic Size of the elements changes:- When we go down the group than the size of the shell increases.

And when we go across the period then the size decreases, because of the force of attraction between the nucleus and the electrons increases.

3. Metallic & Non-Metallic properties:- At lest hand and in the Middle almost every element is a Metal. Non-Metals are lying on the right-hand side. And Metailliod is lies between the metals and the non-metals.

We have discussed each and everything about the Metals and Non-Metals in Our Previous chapter.

What are Metalloids:- Metalloids are the elements that show the properties of both the elements and those are known as the Metalloids. Example:- boron, silicon, germanium, arsenic, antimony, and tellurium are some Metalloids in the periodic table. there are 6 elements known that shows the properties of the Metalloids.

Metallic Characters increase when we move down the group and Metallic character decrease when we move across the period because when we move down the group the tendency to lose the electrons of the elements im=ncreases. But vice-verse when we move across the period.

4. Ionization Energy:- This is the minimum amount of the energy required to remove the electron from its outermost shell.

When we go down in the group the Ionization Energy will require is less. Because of the atomic radius of the atom increases. But when we move across the period then Ionization energy required increases because the atomic radius of the atom decreases.

5. Electron Affinity:- This is the amount of energy released when an isolated neutral gaseous atom in its ground stable to produce on anions.

Here are Our chapter Ends…! [ Class 10th Science Ch-5 Chapter Detailed Notes ]

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