TNPSC Free Notes Chemistry – Periodic Classification of elements Atom

இந்தக் கட்டுரையில், TNPSC குரூப் 1, குரூப் 2, குரூப் 2A, குரூப் 4 மாநிலப் போட்டித் தேர்வுகளான TNUSRB, TRB, TET, TNEB போன்றவற்றுக்கான  முறைகள் இலவசக் குறிப்புகளைப் பெறுவீர்கள்.தேர்வுக்கு தயாராவோர் இங்குள்ள பாடக்குறிப்புகளை படித்து பயன்பெற வாழ்த்துகிறோம்.

Periodic Classification of elements

Atom
 Element is made up of similar, minute particles called atoms.
 The word atom is derived from the Greek word atomos.
 Tomos means smallest divisible particle and atomas means smallest indivisible particle.
John Dalton’s Atomic Theory
John Dalton provided a basic theory about the nature of matter. He proposed a model of atom
known as Dalton’s atomic theory in 1808 based on his experiments.
Fundamental particles of atoms
Protons
The presence of positively charged particles in the atom has been precisely predicted by
Goldstein based on the conception that the atom being electrically neutral in nature, should
necessarily possess positively charged particles to balance the negatively charged electrons.
Electron
J.J. Thomson discovered electrons with the help of cathode ray.
Neutron
In the year 1932, James Chadwick discovered another fundamental particle, called neutron.
Nucleus
 In 1911, Lord Rutherford, a scientist from New Zealand, performed his famous
experiment of bombarding a thin gold foil with very small positively charged particles
called alpha (α) particles. As a result of this experiment Nucleus was discovered.
 It is the combination of Proton and Neutron
 Electrons revolve around in Pathway called orbits
Charges of fundamental particles
 Proton positive Charge
 Electron negative Charge
 Neutron Neutral Charge
Atomic Number
 No. of Protons (or) No. of Electrons in an atom
 It is represented by Z

Example
 Nitrogen Atomic Number = 7
 No. of Electron = 7
 No. of Protons = 7
Mass Number
No. of Protons + No. of Neutrons
Example
 Nitrogen mass number = 14
 Protons Numbers = 7
 Neutron Numbers = 7
Isotopes
Same elements which have same atomic number, but different mass number.

Isobars
Are those elements which have same mass number, but different atomic number.

Isotones

Are those elements which have same number of neutrons

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