Chemistry homework help?
I really need the information.. thanks.
Answer:
In 1805, Dalton created the first atomic model. It is a spherical, featureless ball lack of any visible composition.
In the late nineteenth century. Thomas Thompson created the second atmoic model which we call the Raison bun model.
The raison bun model is made up of uniform composition of protons and electrons in a spherical strucutre. Obviously, he was wrong.
Then, Rutherford created the nuclear model for atom (at the start of twentieth century). This model is created up of the famous gold foil experiment in which he discovered that the positive charges in an atom must be concentrated in the center (a extremely small volume)
Then, there comes Niel Bohr. Niel Bohr, influenced by Einstein's explanation of the famous photoelectric effect (by the new concept of photons) created the planetary model of atom. There are two main aspects of this new concept-the stationary state idea and the transition idea. His model is capable of explaning the visible spectrum of hydrogen, but it's unable of explaining anything that has more than one electrons.
Our present model of atom was first developed in the early 1920s out of Schrodinger's wave equation (as developed from Einstein's wave-particle concept and De Broglie's particle wave concept). In this new model, electrons no longer travelled in a circular path (this was what Bohr and Rutherford thought the electrons were doing) but in certain orbitals of unique 3-D shape. These orbitals, as given by the names of s-p-d-f., were created as solutions of the wave equation. One big aspect of this model was that we could not predict the momentum and the velocity of electrons at any given time-Hunsenburg's Uncertainty Principle.
Hope this helps, and of course hope it's not too long:p
Bohr's Model :
Thomson Model :
Rutherford's Model :
hmm..some of the atomic models i know are:
plum-pudding by jj thomson
gold-foil atomic model by rutherford
atomic model by niels bohr
by sommerfield
and many more..
however, you may still visit these sites for further clarifications...
http://www.chemsoc.org/timeline/pages/19...
http://mhsweb.ci.manchester.ct.us/librar...
http://library.thinkquest.org/19662/low/...
http://online.cctt.org/physicslab/conten...
hope i'd helped you...(and vote me as the best answer...lol)
:-)
john dalton proposed the atomic theory in1808 but daltons atomic model had it weakness.then in 1897,j.j thomson discovered negatively charged particles which called electrons.
in 1911 ernest rutherford bombarded a thin gold foil with alpha particles(helium nuclei, He).rutherford proposed that an atom consists of positively charged nucleus with a cloud of eletrons surrounding the nucleus.in 1913,niels bohr the electrons in the atom are arrangad in electron shell.
in 1932,james chadwic discovered rays of electrically neutral subatomic particles which he callen neutrons.the atomic in the present day is based on the contributions of chadwick.
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