
	Where results make sense

Topic: Bohr atom model

Related Topics

Atomic physics

In the News (Sat 26 Dec 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	O=CHemBohrModel
		The model bears his name because of his interpretation of the emission spectrum of hydrogen: If a small amount of hydrogen gas is confined within a glass tube and subjected to a high voltage, it emits light, some of which falls in the visible region of the electromagnetic spectrum.
		Bohr knew that the emission of light was the way the atoms released the energy they had absorbed when the high voltage was applied.
		Bohr's success in rationalizing the emission spectrum of hydrogen led to the general acceptance of the planetary model of the atom.
	www.usm.maine.edu /~newton/Chy251_253/Lectures/BohrModel/BohrModel.html (365 words)

	Bohr model
		In physics the Bohr Model, still commonly used and taught today because of its simplicity, depicts the atom as a small positively charged nucleus with electrons in orbit at different levels, similar in structure to the solar system.
		The simplest possible atom is hydrogen, which consists of a nucleus and one orbiting electron.
		The Bohr model is sometimes known as the semiclassical model because although it does include some ideas of quantum mechanics it is not a full quantum mechanical description of the atom.
	www.ebroadcast.com.au /lookup/encyclopedia/bo/Bohr_model.html (774 words)

	The Bohr atom
		The planetary model of the atom assumed that the electrostatic attraction between the central nucleus and the electron is exactly balanced by the centrifugal force created by the revolution of the electron in its orbit.
		Bohr suggested that the planetary model could be saved if one new assumption were made: certain "special states of motion" of the electron, corresponding to different orbital radii, would not result in radiation, and could therefore persist indefinitely without the electron falling into the nucleus.
		Specifically, Bohr postulated that the angular momentum of the electron, mvr (the mass and angular velocity of the electron and in an orbit of radius r) is restricted to values that are integral multiples of h/2π.
	www.chem1.com /acad/webtext/atoms/atpt-3.html (2600 words)

	Bohr model Summary
		Atoms with electrons in their lowest energy orbits are in a "ground" state, and those with electrons jumped to higher energy orbits are in an "excited" state.
		Introduced by Niels Bohr in 1913, the model's key success was in explaining the Rydberg formula for the spectral emission lines of atomic hydrogen; while the Rydberg formula had been known experimentally, it did not gain a theoretical underpinning until the Bohr model was introduced.
		The Bohr model is a primitive model of the hydrogen atom which cannot explain the fine structure of the hydrogen atom nor any of the heavier atoms.
	www.bookrags.com /Bohr_model (4442 words)

	Copenhagen . Niels Bohr \| PBS
		Bohr postulated that radiation is emitted from atoms not as a result of the periodic motion of the electron in its orbit, but only when an electron "jumps" from one orbit to another losing energy that is emitted as radiation.
		Bohr's theory of the compound nucleus, in which the repulsion between positively charged protons is countered by huge amounts of energy in order to hold the nucleus together, helped lead to the hypothesis that splitting an atom would produce enough energy to fabricate a powerful weapon.
		Bohr earned his Ph.D. at the University of Copenhagen in 1911, then worked in Cambridge, England with J.J. Thomson, discoverer of the electron, and in Manchester with Rutherford, who proposed the first nuclear model of the atom.
	www.pbs.org /hollywoodpresents/copenhagen/story/bohr.html (558 words)

	The Bohr Model
		The Bohr Model is probably familar as the "planetary model" of the atom illustrated in the adjacent figure that, for example, is used as a symbol for atomic energy (a bit of a misnomer, since the energy in "atomic energy" is actually the energy of the nucleus, rather than the entire atom).
		In the Bohr Model the neutrons and protons (symbolized by red and blue balls in the adjacent image) occupy a dense central region called the nucleus, and the electrons orbit the nucleus much like planets orbiting the Sun (but the orbits are not confined to a plane as is approximately true in the Solar System).
		This similarity between a planetary model and the Bohr Model of the atom ultimately arises because the attractive gravitational force in a solar system and the attractive Coulomb (electrical) force between the positively charged nucleus and the negatively charged electrons in an atom are mathematically of the same form.
	csep10.phys.utk.edu /astr162/lect/light/bohr.html (711 words)

	Bohr model - Wikipedia, the free encyclopedia
		The Bohr model is a primitive model of the hydrogen atom.
		Bohr proposed that a new kind of mechanics, or quantum mechanics, describes the motion of the electrons around the nucleus.
		In the end, the model was abandoned in favour of the full quantum mechanical treatment of the hydrogen atom, in 1925, using Schrödinger's wave mechanics.
	en.wikipedia.org /wiki/Bohr_model (2211 words)

	Bohr's atom model
		According to the Rutherford's model of atom the electrons places outside the nucleus must circulate around it on some orbits.
		Having this formula one can calculated the radius each and every orbit of the Bohr atom - the values of the square brackets are known and n is an integer equal 1 or bigger (for n = 1 one gets the r of the first stationary orbit).
		The frequencies of radiation calculated by Bohr for the successive electron transitions is in agreement with an experimental data (the spectrum lines of hydrogen).
	library.thinkquest.org /19662/low/eng/model-bohr.html (1463 words)

	Bohr's Atomic Model
		Bohr said that the electron had to release energy to change its energy so the differences between the energies of light seen in the atomic spectrum should correspond to the differences in energies of the energy levels.
		Bohr proposed that each orbit was defined by a certain energy so he said that the electron was in an energy level.
		Bohr's definition of an orbital turned out to be too defined: the quantum mechanical versions of an orbital in much different: but the idea that only certain orbitals exist still holds true in the quantum mechanical model.
	students.ed.uiuc.edu /swires/CAP/bohr.htm (629 words)

	The Bohr Atom
		Bohr concluded that in an atom in its natural rest state, the electron must be in a special orbit, he called it a "stationary state" to which the usual rules of electromagnetic radiation didn't apply.
		Bohr suggested in a note to Rutherford in the summer of 1912 that requiring this energy be some constant (assumed to be of order of magnitude one) multiplied by hf would fix the size of the atom.
		Therefore, Bohr concluded K is fixed by requiring that the frequency of radiation emitted by a really large atom be correctly given by ordinary common sense -- that is, the frequency of the radiation must be the same as the orbital frequency of the electron, the number of cycles a second.
	galileo.phys.virginia.edu /classes/252/Bohr_Atom/Bohr_Atom.html (2892 words)

	Bohr model of the atom (Site not responding. Last check: 2007-11-03)
		Rutherford, who had a few years earlier, discovered the planetary model of the atom asked Bohr to work on it because there were some problems with the model: According to the physics of the time, Rutherford's planetary atom should have an extremely short lifetime.
		Bohr's model of the atom revolutionized atomic physics.
		Bohr's model was so successful that he immediately received world-wide fame.
	www.iun.edu /~cpanhd/C101webnotes/modern-atomic-theory/Bohr-model.html (269 words)

	Niels Henrik David Bohr Biography \| Encyclopedia of World Biography
		Niels Bohr was born on Oct. 7, 1885, in Copenhagen, the son of Christian Bohr and Ellen Adler Bohr.
		As Bohr himself recalled in 1934, "As soon as I saw Balmer's formula the whole thing was immediately clear to me." The "thing" was the recognition on Bohr's part that basically different laws govern the atom when it is not in its stationary state but is absorbing or emitting radiation.
		When Bohr asked Rutherford to recommend his now historic paper "On the Constitution of Atoms and Molecules" for publication, Rutherford admitted that Bohr's ideas as to the mode of origin of the spectra of hydrogen were very ingenious and worked very well, but he was unwilling to agree with Bohr's own evaluation of the paper.
	www.bookrags.com /biography/niels-henrik-david-bohr (1573 words)

	Bohr Atomic Model (Site not responding. Last check: 2007-11-03)
		The motion of the electrons in the Rutherford model was unstable because, according to classical mechanics and electromagnetic theory, any charged particle moving on a curved path emits electromagnetic radiation; thus, the electrons would lose energy and spiral into the nucleus.
		Bohr's starting point was to realize that classical mechanics by itself could never explain the atom's stability.
		Bohr noticed, however, that the quantum constant formulated by the German physicist Max Planck has dimensions which, when combined with the mass and charge of the electron, produce a measure of length.
	abyss.uoregon.edu /~js/glossary/bohr_atom.html (623 words)

	Chapter Nine The Bohr Model of the Atom (Site not responding. Last check: 2007-11-03)
		Bohr knew that light was absorbed and emitted by atoms.
		Bohr's answers to these questions were one of the first triumphs of the new Quantum Theory.
		Bohr used the ideas and principles from Quantum mechanics to suggest a model of the hydrogen atom.
	www.chem.ufl.edu /~chm2040/Notes/Chapter_9/bohr.html (525 words)

	Bohr Model
		Rutherford’s discovery set the stage for Bohr’s orbital model of the atom, which utilized the idea of a central nucleus.
		Bohr calculated an equation for his model that gave simplistic values for the radii at which the electrons could orbit.
		The jump is caused by a quantized radiation that hits the atom and transfers the electron to another stationary state.
	library.thinkquest.org /28582/history/bohr.htm (571 words)

	The Case Against the Nuclear Atom - Chapter Eight
		Schrodinger himself accepted (with some reservations) the currently popular nuclear atom as a model, a useful conceptual device, but it is evident from the statement which was quoted at the end of Chapter 3, that he did not regard it as a picture.
		The atom itself was originally nothing but a model-a model of the structure of matter-but we now feel certain that atoms actually exist, since we have accumulated a vast amount of information pointing to the existence of such units and no significant evidence to the contrary.
		Bohr's original theory of the atom, for example, was based on a completely erroneous assumption, as has been pointed out in the preceding pages, and has now been repudiated by the originator and his associates (on other grounds), but it cannot be denied that it has served a very useful purpose.
	www.reciprocalsystem.com /cana/cana08.htm (2723 words)

	Bohr's Model of the Hydrogen Atom (Site not responding. Last check: 2007-11-03)
		Bohr began with the assumption that electrons were orbiting the nucleus, much like the earth orbits the sun.
		Bohr's model of the atom was important because it introduced quantized energy states for the electrons.
		However, as a model it was only useful for predicting the behavior of atoms with a single electron (H, He and Li ions).
	wine1.sb.fsu.edu /chm1045/notes/Struct/Bohr/Struct03.htm (955 words)

	Electromagnetic Radiation
		Some models of the atom were similar to our current one: the positive charges are concentrated in a central nucleus with the negative charges swarming around it, but the atoms should be unstable.
		In Bohr's model of the atom, the massive but small positively-charged protons and massive but small neutral neutrons are found in the tiny nucleus.
		Atoms want to be in the lowest possible energy state called the ground state (all electrons as close to the nucleus as possible).
	www.astronomynotes.com /light/s7.htm (806 words)

	The Bohr Atom
		The nuclear atom proposed by Rutherford was unstable.
		Bohr obtained the value of radius of hydrogen atom and its energy, both of which agree well with experimental results.
		Thus, within the Bohr atom framework, it is valid for He, Li, Be etc. Let us consider the case of an ion with the charge of nucleus being Ze and an electron moving with a constant speed v along a circle of radius r with the center at the nucleus.
	venables.asu.edu /quant/Dinesh/Bohratom2.html (988 words)

	Bohr's Atom - SciForums.com
		In grammar school I was taught Bohr's model of the atom.
		Bohr's atom model is incorrect (I am not sure it was believed to be true THEN either).
		When Schrodinger formulated the equation that now bears his name, and applied it to the hydrogen atom, he found found a set of functions as a solution to this that describes the bound electron states (I am delibrately not using the word "orbital" as this may lead to an analogy to the classical planetary model).
	www.sciforums.com /showthread.php?t=20903 (1406 words)

	The Bohr Model of the Atom
		Bohr argued that Planck's constant should be used to help account for the stability of the atom.
		Bohr also realized that, if he was correct, his theory should produce a constant with the units of length.
		By the introduction of this quantity the question of the stable configuration of the electrons in the atoms is essentially changed as this constant is of such dimensions and magnitude that it, together with the mass and charge of the particles, can determine a length of the order of magnitude required.
	dbhs.wvusd.k12.ca.us /webdocs/Electrons/Bohr-Model-part1.html (1361 words)

	Atoms
		The binding energy of the helium atom, which has two electrons, was not understood until the development of quantum mechanics.
		They passed a beam of silver atoms through a nonhomogeneous magnetic field, one that is stronger on one side than on the other.
		In spite of these modifications, Bohr's model seemed to be a dead end by the early 1920s.
	members.tripod.com /nielsbohr/temp/atoms.htm (1505 words)

	Quantum Theory (Site not responding. Last check: 2007-11-03)
		Bohr's atom model was remarkably successful in describing the spectrum of the hydrogen atom by using Planck's formula to relate different energy levels of electrons to different frequencies of light radiation.
		Bohr's model of the atom was superseded by the probability cloud model that describes physical reality better.
		The computation of the actual distribution of electrons in an atom is extremely laborious and the result is too complicated to be illustrated in a single layer 3D model.
	www.thebigview.com /spacetime/quantumtheory.html (1990 words)

	Objections To The Bohr-Rutherford Model
		All of whom raised valid objections to the Bohr model from the outset....
		Bohr’s insistence that the accelerated motion of electrons within the atom do not radiate is logically objectionable.
		The presence of a high concentration of hydrogen atoms would presumably organize the local vacuum flux to provide a strong background signal for the production of hydrogen from neutrons, which just so happens to be the normal decay route for neutrons.
	www.lnhatom.com /bohrrutherford.html (1616 words)

	The Relativistic Bohr Model of a Hydrogen-like Atom
		The Bohr model of the atom was replaced by the Quantum Mechanics model based upon the Schroedinger equation in the 1920's.
		The model would equally well apply to an electron in orbit about a nucleus with a positive charge of Z (a hydrogen-like atom), in which case the value of γ would be Z/137.036.
		For the l=3 to l=2 transition the predicted wavelength of the conventional Bohr model is 102.627 nm, an error of 0.0429 of 1%.
	www.applet-magic.com /relabohr.htm (1124 words)

Try your search on: Qwika (all wikis)