Chemistry:
Collect information regarding periodical development of fundamental
particles and structure of atom with different atomic models and display
then information Chart.
Answers
Answer:
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please mark as brainliest answer.
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The ancient Greek philosophers played a significant role in shaping the initial thoughts about atoms and early atomic theories.
Concept of Thales :
According to him “Every thing in the world is made up of water “.
Concept of Anaximenes :
According to him “Every thing in the world is made up of Air”
Maharishi Kanad was a great Indian sage in Vedic period.
His contribution to chemistry is he was the first man to propound the idea of ultimate particle of matter as 'anu' and 'paramanu'.
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Dalton’s Atomic Theory :
All matter is composed of tiny particles called as atoms.
Atoms cannot be divided up into the smaller particles and cannot be destroyed.
Atoms of an element all have same mass and properties
Atoms of different elements have different masses and different properties.
Atoms combine in simple whole numbers when they form compounds.
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Discovery of Subatomic particles:
Discovery of Electron:
In 1897, J.J. Thomson used a cathode ray tube to deduce the presence of a negatively charged particle: the electron
The electron is the negatively charged particle found in the atoms of all the elements. Electrons are located outside the nucleus in an atom.
An electron is usually represented by e-
Discovery Of Proton :
Discovered by E. Goldstein (German) in 1886. The proton is the positively charged particle found in the atoms of all elements.
The protons are located in the nucleus of atom.A proton is usually represented by p+
Discovery of Neutrons
James Chadwick discovered neutrons in the year 1932. Neutron is the neutral particle found in the nucleus of an atom.
Neutron is represented by symbol n.
***************************************************************************\ Thomson’s model:
- 1. An atom consists of a sphere of positive charge with negative carged electrons embedded in it.
- 2. The positive and negative charges in an atom are equal in magnitude, due to which atom is electrically neutral. These equal and opposite charges balance each other.
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- Rutherford proposed his model of the structure of the atom. According to this model –
- Electrons surround the nucleus and move around it at very high speeds in circular paths called orbits. This arrangement also resembles the solar system, where the nucleus forms the sun and the electrons are the revolving planets.
- Therefore, it is also referred to as the Planetary Model.
- Electrostatic forces of attraction hold the nucleus and electrons together.
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Neil Bohr overcame the limitations of Rutherford model and proposed a model of atomic structure.
Following are the postulates:
An atom consists of heavy positively charged nucleus. The whole mass of the atom is concentrated in the nucleus.
The electrons in an atom revolve around the nucleus in definite circular paths called orbits or energy level.
The energy levels are represented either by numbers 1,2,3,4 and so on or by letters K,L,M,N,O and P
Each energy level is associated with definite amount of energy.
The change in energy takes place when electron jumps from one energy level to another energy level.
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