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Solid Sphere Model
The Solid Sphere Model was the first atomic model and was developed by John Dalton in the early 19th century. He hypothesized that an atom is a solid sphere that could not be divided into smiller particles. He camne up with this theory as a result of his research into gases.
His discoveries are important because the made possible modern chemistry and physics.
It was wrong beacuse Dalton did not realize that atoms were made up of smaller particles. -
Plum Pudding Model
J.J 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 as spherical cloud of positive charge.
It is important because it recognised electrons as components of atoms.
It was wrong because he did not considered the nucleus. -
Nuclear Model
Ernest Rutherford fired positively charged alpha particles at a thin sheet of gold oil. Most passed thrrough with litte 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.
It is important because he realsed positive charge was located in the nucleus of an atom.
But it is wrong because he didn´t explain why electrons remain an orbit around the nulceus. -
Planetary Model
Niels Bohr modified Rutherford´s model of the atom by starting that electrons moved around the nucleus in orbits of fixed sizes and energies. Electron energy in this model was quatised; electrons could not occupy values of energy between the fixed energy levels.
It was important because it proposed stable electron orbits, but it was wrong because he did not consider moving electrons should emit energy and collapse into the nucleus and the model did not work well of the heavier atoms. -
Quantum Model
Erwin Shrodinger started that electrons do not move in set paths around the nucleus, but in waves. It is impossible to know the location of the electrons; instead, we have ´clouds of probability´ called orbitals, in which we are more likelyto find an electron.
It is important because it shows that elctrons don´t move around the nucleus in orbits, but in clouds were their position is uncertain.
It hasn´t been prove wrong yet.
