Science - Teachers Sri Lanka

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That,
² Atom is a particle with a small mass.
² Fundamental sub atomic paticles inclued in an atom
are electrons,protons and neutrons.
² Out of the paticles the lightest particle is the
electron.
² mass of an electron is about 9.1095x 10 -31 kg
² electron is a particle with a negative charge.
² Scientists J.J Thompson,Millikan Cotributed to the
fundamental studies about the electron .
² Proton is a partical having a mass of about 1840
times the mass of an electron.
² Mass of a proton is about 1.6725x10 -31 kg
² Proton is a particle with a positive charge.
² Proton is symbolised as 1 p 1
² Ernest Rutherford contributed to the fundamental
studies about the proton.
² Neutron is a partical which has a mass almost equal
to that of a proton.
² Mass of a neutron is about 1.6750x10 -20 kg.
² Neutron is a particle with no charge,it is neutral.
² Neutron is symbolised as 1 n 0
² The number of electron or the number of protons in
an atom of an element is identical to that element.
² According to J.J Thompasons"Plum pudding "model
he stated that an atom is a sphere which is positively
charged,and the electrons which are negatively
charged are embeded in it.
² According to Rutherford solar model the protons,and
neutrons are collected at the centre which is the
nucleus and the electrons are moving in orbits around
it.
² These shells are named as K.L.M.N from centre
out wards
(45 mts)
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