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Category: Altro
è stato aggiornato: 15 gen 2023
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Created byДмитрий Грязнов
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Democritus (Greek Model)
Democritus' model claimed that matter
consists of invisible particles called atoms and
emptiness (empty space). He claimed that
atoms are indestructible and unchangeable. In
addition, they are homogeneous, that is, they
do not have an internal structure. His atomic
model was solid and stated that all atoms differ
in size, shape, mass, position and location, and
there is a void between them.Dalton's model of the atom
John Dalton suggested that all matter consists
of very small particles - atoms. He concluded
that atoms are small spherical particles that
cannot be separated further. All atoms of the
same element are equal to each other. They
have the same volume and mass. Atoms of
different elements differ in volume and mass.
There are as many types of atoms as there are elements.Thomson's model of the atom
After the electron was discovered by J.J.
Thomson in 1897, people realized that atoms
were made up of even smaller particles than
they had previously thought. However, the
atomic nucleus had not been discovered yet
and so the “plum pudding model” was put
forward in 1904. In this model, the atom is
made up of negative electrons that float in a
“soup” of positive charge, much like plums in a
pudding or raisins in a fruit cake.Rutherford's model of the atom
Rutherford’s new model described the atom as
a tiny, dense, positively charged core called a
nucleus surrounded by lighter, negatively
charged electrons. Another way of thinking
about this model was that the atom was seen
to be like a mini solar system where the
electrons orbit the nucleus like planets orbiting around the sun.Bohr's model of the atom
There were some problems with Rutherford's model:
for example, it could not explain the very
interesting observation that atoms only emit
light at certain wavelengths or frequencies.
Niels Bohr solved this problem by proposing
that the electrons could only orbit the nucleus
in certain special orbits at different energy
levels around the nucleus
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