Have the models of atoms changed over the years?

Answer 1

The pretty universally accepted model from the time we first began to suspect (with some actual evidence, as opposed to being ancient Greeks pulling theories out a posteriori) that there were such things as atoms was that they were small, indivisible ... well, probably spheres. At least some of them were probably spheres, anyway.

Around 1900 it became clear that while "small" was still true, "indivisible" was ... not so much. This lead to several competing theories that came out all about the same time (within a decade or so, anyway; 1902 to 1911): the cubic model, the "plum pudding" model, the "Saturnian" model, and the "Rutherford" model. All of these were attempts to explain the newly-discovered electrons and what exactly they were doing inside atoms.

In 1913 Niels Bohr modified the Rutherford model a bit (incorporating some pieces of the Saturnian model as well) and came up with the Bohr model, which proposed that the electrons orbited a concentration of positive charge in the center of the atom in well-defined circular orbits. The Bohr model accounted for the fact that the electrons didn't immediately radiate energy and spiral into the nucleus by proposing that they were confined by ... something ... into specific orbits having characteristic energies. An electron could jump from one orbit to another (provided there was a space open), but only by giving off energy exactly equal to the difference in energy between the two orbits. This accounted for the observed phenomenon that atoms did in fact give off energy of very specific, or quantized, values.

There were still problems with the Bohr model, one of which was that there didn't seem to be any particular reason the energy levels should happen to be what they were, so the Bohr model eventually disappeared in favor of the current quantum mechanical model, which describes the electrons as being in eigenstates of the time-dependent Hamiltonian equation, accounting precisely for their energies.

Answer 2

Yes the model of an atom has changed over time.

The first model was proposed by John Dalton and was nothing but a dot of mass. He said that there were different types of atoms for different substances, but atoms were the smallest possible thing and could be broken down no more.

He was proved wrong by J. J. Thomson, who found out that atoms were actually composed of subatomic particles, but the only particle he discovered was the electron. His theory of what an atom looked like was called the plum pudding theory or the chocolate chip cookie dough theory because it was just a circle (positively charged space) filled with dots (electrons).

Another man named Ernest Rutherford found out that an atom had a nucleus in the center that was positively charged, and the diagram for an atom changed yet again to a circle with a big dot in the middle (the nucleus; a proton) with little dots scattered around it (electrons).

The present day model for an atom was completed by James Chadwick, who found out that the nucleus also consisted of neutrally charged particles called neutrons.

Answer 3

New discoveries and technology allowed scientists to figure out more and more properties of atoms as time passed, so they had to keep tweaking and refining the model. Even the one we use today is not guaranteed to be completely accurate.

Answer 4

Yes, models of atoms have evolved over time as our understanding of atomic structure has improved. From the early plum pudding model, to the planetary model, to the current model of the atom based on quantum mechanics, our understanding of atoms has become more sophisticated and accurate. These models have been developed based on experimental evidence and theoretical insights.

Answer 5

because how we thought they were composed turned out wrong and corrections were made accordingly.

Answer 6

It started with Einstein's theory e=mc2 and after research by scientists all over the world, became what it is today.

Answer 7

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Answer 8

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