The

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The
Atom
Created by Suresh A Baby Smitha Christ Nagar
EHSS
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Introduction

• Each and every material that make our beautiful
  earth are made up of very small particles called
  atoms.
• Let us study more about atoms

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Atoms

• John Dalton discovered atoms
• An element contains atoms of the same
  kind.
• A compound contains different types of atoms.

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The fundamental particles of an atom

• An Atom contains three types of fundamental
  particles.
• They are

NEUTRONS
PROTONS
ELECTRONS
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Charge and Mass of the Fundamental
particles
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PLANETARY MODEL OF THE ATOM

• Rutherford pictured atom as a miniature solar
  system.
• The atom has a small central portion called
  nucleus which accomodates protons and neutrons.
• The electrons revolve round the nucleus just like
  the planets revolve round the sun in the solar
  system
• But this model failed to explain many properties
  of the atom

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• According to Bohr, a revolving electron in any
  particlular orbit is associated with a defenite
  quantity of energy and hence the orbits are known
  as energy levels.
• Even Bohrs model was inadequate to explain many
  facts about the behavior of the atom

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Modern Theory of the Atom.

• A more modern theory of the atom was developed
  under the leadership of Schrodinger.
• According to this theory electrons are clouds of
  negative charges which show the characteristics
  of both particles and waves.
• The locations of the electrons are treated as
  probabilities (Orbitals)

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ORBIT AND ORBITAL

• An Orbit is a path around the nucleus of an atom
  through which an electron moves.
• An Orbital is the three dimensional space around
  the nucleus of an atom where the probability of
  finding electron is greater.

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Atomic Number and Mass Number.

• The number of protons present in the nucleus of
  an atom of an element is known as its atomic
  number.
• The total number of protons and neutrons in the
  nucleus of an atom of an element is known as its
  mass number.

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Isotopes

• Atoms of the same element which has
• the same atomic number, but different mass
  number are known as isotopes.
• They differ in the number of neutrons in their
  nucleus.

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Isotopes of Hydrogen

• The isotopes of hydrogen are
• Protium, Dueterium and Tritium

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Conclusion

• Atom which is the smallest particle of a
  substance is made up of protons, electrons and
  neutrons.
• Protons and neutrons occupy a small central
  portion called nucleus.
• Electrons revolve round the nucleus in orbitals.

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Bibliography

• www.msn.com
• The End THE END