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ATOM - Coggle Diagram
ATOM
DEVELOPMENT OF ATOM
1803 JOHN DALTON
Dalton drew upon the Ancient Greek idea of atoms. His theory stated that atoms are indivisible, those of a given element are identical, and compounds are combinations of different types of atoms.
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1904 J.J. THOMSON
Thomson discovered electrons in atoms in 1897 for which he won a Nobel Prize. He subsequently produced the “plum pudding” model of the atom. It shows the atom as composed of electrons scattered throughout a spherical cloud of positive charge.
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1911 ERNEST RUTHERFORD
Rutherford fired positively charged alpha particles at a thin sheet of gold foil. Most passed through with little deflection, but some deflected at large angles. This was only possible if the atom was mostly empty space, with the positive charge concentrated in the centre: the nucleus.
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1913 NEILS BOHR
Bohr modified Rutherford’s model of the atom by stating that electrons moved around the nucleus in orbits of fixed sizes and energies.
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1926 ERWIN SCHRODINGER
Schrodinger stated that electrons do not move in set paths around the nucleus, but in waves.
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1932 JAMES CHADWICK
Chadwick made a fundamental discovery in the domain on nuclear science. Neutrons were involved in creating nuclear explosions and nuclear energy, for it is by bombardment with high-energy neutrons that scientists first learned how to split an atom.
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STRUCTURE OF ATOM
A Neutron is the neutral part of the atom’s nucleus, with no electric charge, and a mass slightly larger than that of a proton.
An Electron is a negatively charged part of the atom found outside the nucleus in orbits and are attached to the protons in the atom with electromagnetic force. Closer the electron to the nucleus, the stronger the electromagnetic force between them.
A Proton is a positively charged particle found within the atom’s nucleus. Rutherford discovered them in his experiments with cathode ray tubes.
The Nucleus is the positively charged centre of an atom and contains most of its mass. It is composed of protons, which have a positive charge, and neutrons, which have no charge.
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Atom, smallest unit into which matter can be divided without the release of electrically charged particles. It also is the smallest unit of matter that has the characteristic properties of a chemical element. As such, the atom is the basic building block of chemistry.
