Question

$\huge\underline\mathfrak\red{Hiyu\:brainliacs}$ ❤️


Question :

Give a brief introduction of chapter "periodic classification of elements"



class 10th !! ​

Answer 1

Hi friend here is your answer

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PART - 1

A) Earlier attempts of classification

1) Dobereiners traids (1829)

He found out a group of three elements having similar properties where the atomic weight of central atom is approx mean of other two

2) Newland octaves

Properties of every eights element are similar to the first one applicable only upto calcium

3) Lother Meyers graph

He plotted atomic volume against atomic weights and found that similar elements occupy similar position

4) Mendeleevs work

his periodic law properties of elements are periodic function of atomic masses

Germanium - Eka-silicon

Gallium - Eka-aluminum

B) Modern Periodic Table

Merits

1) Base is atomic no and electronic configuration

2) Clear does not division of elements into 4 blocks

3) Easy to remember position of elements

Demerits

1) Position of Hydrogen with alkali metals

2) f Block has not been given position in main Table

3) as per EC of He 1s2 it should be placed with alkaline earth metals

PART - 2 (coming up after a short break XD)

PERIODIC PROPERTIES

1) Atomic Radius & Ionic radius

Along a period atomic and ionic radius decrease because of addition of electrons in orbits of same shell

# In every period largest size is of alkali metal and smallest is of Halogen

2) Ionisation Enthalpy

Ionisation energy is the metallic property coz metals lose electrons easily

It is the energy required to remove the electron from outermost Valence shell

Values if Ionisation enthalpy depends on half files or full filled type of configurations

3) Electron gain enthalpy

It is nonmetallic property coz non metals gain electrons

Down the group electron affinity decrease

4) Electronegativity

Along period increases

Along group decreases

It is inversely to size of atom

Further on there is Pauling and Muliken scale but I think it's enough for class 10th

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Hope it helps you................!!

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Day One ish

Answer 2

I hope it's helpful for you

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