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Topic: Aufbau Principle

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	Aufbau Corporation \| About The Name
		The principle is an application of the laws of quantum mechanics to the properties of electron subject to the electric field created by the positive charge on the nucleus.
		The building-up denoted by the name of the principle is a process in which electrons are regarded as entering one by one this electric field assuming their most stable conditions with respect to it.
		Under Aufbau Principle electrons are placed as close to the bottom of an energy level as possible, as an electron cannot occupy a higher level unless the lower levels of an atom are provided with the necessary electrons to fill the level.
	www.aufbau.com /aboutname.htm (276 words)

	The Aufbau Principle
		The aufbau principle is really a thought process in which we think about building up an atom from the one that preceeds it in atomic number, by adding a proton and neutrons to the nucleus and one electron to the appropriate atomic orbital.
		The reason for these and other exceptions are not completely understood, but it seems that a half-filled 3d subshell in the case of chromium or a completely-filled 3d subshell in the case of copper lend a special stabilty to the observed electron configurations.
		There is no need to dwell on these exceptions, the point to remember is that the aufbau principle predicts the correct electron configuration most of the time and that the energy of the predicted electron configuration is very close to the ground state energy.
	chemistry.twu.edu /tutorial/AufbauSum.html (0 words)

	Spartanburg SC \| GoUpstate.com \| Spartanburg Herald-Journal
		Electrons are able to move from one energy level to another by emission or absorption of a quantum of energy, in the form of a photon.
		In the ground state of an atom (the condition in which it is ordinarily found), the electron configuration generally follows the Aufbau principle.
		The Aufbau principle can be applied, in a modified form, to the protons and neutrons in the atomic nucleus (see the shell model of nuclear physics).
	www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=p_orbital (1350 words)

	Aufbau principle
		Associated with each n is a principle energy level known as a shell.
		The atomic structure is, in turn, determined by the electrons and which shells, subshells and orbitals they reside in.
		The rules af placing electrons within shells is known as the Aufbau principle.
	www.iun.edu /~cpanhd/C101webnotes/modern-atomic-theory/aufbau-principle.html (0 words)

	[No title]
		An introduction to the principles of quantum mechanics is presented here.
		It is intended to supplement the discussion of hydrogen and many-electron orbitals commonly found in general chemistry text books with a deeper understanding of the underlying physical principles.
		The relationship between classical and quantum mechanics is explored to illustrate how physical objects can be viewed both as a particle and a wave.
	www.chemistry.ohio-state.edu /betha/qm (124 words)

	General Chemistry Online: Glossary: Electrons in atoms
		A model of the atom that explains emission and absorption of radiation as transitions between stationary electronic states in which the electron orbits the nucleus at a definite distance.
		The Bohr model violates the Heisenberg uncertainty principle, since it postulates definite paths and momenta for electrons as they move around the nucleus.
		quantum number has only two possible values, the Pauli principle says that a maximum of two electrons can occupy an atomic orbital- and these electrons must have opposite spins.
	antoine.frostburg.edu /chem/senese/101/electrons/glossary.shtml (0 words)

	[No title]
		Which quantum number is a result of two electrons of opposite spins occupying the same orbital?
		Given an element with a principle quantum number of 4, which atomic orbital orbital will be filled first in the valence shell?
		In degenerate orbitals, each orbital is filled with one electron before any orbital obtains a second electron.
	www.ualr.edu /rebelford/chem1402/q1402/X3/C8/8-3/8-3.htm (0 words)

	AUFBAU1 [TEACHER'S NOTES]
		In principle, Chemistry is the subject par excellence for developing a student's cognitive, literacy, mathematical, and practical skills: if, and only if, a course reflects a balance of the various strands; i.e., biological, industrial, inorganic, organic, physical, and practical.
		In Abundances, the content is the abundances of elements (derived, importantly, by the application of a principle introduced in Chemical Calculations); the mathematical and practical skills being developed are good practices in the construction of graphs.
		And finally, the section from Strontium through to Platinum, which neither follows the electrochemical series nor introduces any new principles, but which does keep to within the spirit of the syllabus, was designed to allow students to appreciate the richness of Chemistry.
	www.wissensdrang.com /auf1tn.htm (3678 words)

	International Union of Pure and Applied Chemistry
		Antisymmetry principle (synonymous with the Pauli exclusion principle) - The postulate that electrons must be described by wavefunctions which are antisymmetric with respect to interchange of the coordinates (including spin) of a pair of electrons.
		A corollary of the principle is the Pauli exclusion principle.
		All particles with half-integral spin (fermions) are described by antisymmetric wavefunctions, and all particles with zero or integral spin (bosons) are described by symmetric wavefunctions.
	www.iupac.org /reports/1999/7110minkin/a.html (2039 words)

	Atomic Evolution
		Known as the Pauli exclusion principle, it formed the basis of the electronic structure in atoms.
		What this principle states is that no two electrons in an atom can have the same set of four quantum numbers (n, l, ml, ms).
		This process of starting at the bottom and working up is commonly known as the Aufbau principle, Aufbau being derived from German, meaning "building-up".
	library.thinkquest.org /C0110925/html/theatom/manyelectronatoms/manyelectronatoms5.html (186 words)

	[No title]
		Pauli exclusion principle The requirement for electrons (or other fermions) that the wavefunction for a collection of such particles is antisymmetric under interchange of the position and spin coordinates of any pair of identical particles.
		This principle clearly relates the quantum theory to the observed properties of atoms.
		The nature of the Pauli exclusion principle can be illustrated by supposing that electrons 1 and 2 are in states a and b respectively.
	www.lycos.com /info/pauli-exclusion-principle.html (342 words)

	Aufbau principle Information (Site not responding. Last check: )
		The Aufbau principle (also Aufbau rule or building-up principle), is used to determine the electron configuration of an atom, molecule or ion.
		The principle postulates a hypothetical process in which an atom is "built up" by progressively adding electrons.
		A version of the Aufbau principle can also be used to predict the configuration of protons and neutrons in an atomic nucleus.
	www.bookrags.com /wiki/Aufbau_principle (236 words)

	SparkNotes: Atomic Structure: Electron Configuration and Valence Electrons
		The electrons in an atom fill up its atomic orbitals according to the Aufbau Principle; "Aufbau," in German, means "building up." The Aufbau Principle, which incorporates the Pauli Exclusion Principle and Hund's Rule prescribes a few simple rules to determine the order in which electrons fill atomic orbitals:
		The configuration is determined by applying the rules of the Aufbau Principle.
		In other words, once we get to principle quantum number 3, the highest subshells of the lower quantum numbers eclipse in energy the lowest subshells of higher quantum numbers: 3d is of higher energy than 4s.
	www.sparknotes.com /chemistry/fundamentals/atomicstructure/section2.rhtml (988 words)

	Aufbau principle definition - Dictionary - MSN Encarta
		Aufbau principle definition - Dictionary - MSN Encarta
		Search for "Aufbau principle" in all of MSN Encarta
		theory of element creation: a principle that each successive chemical element in a sequence can be created by adding a proton to the nucleus and an electron to an orbital of the preceding element
	encarta.msn.com /dictionary_561532683/Aufbau_principle.html (97 words)

	Aufbau principle - Wikipedia, the free encyclopedia
		The number of electrons that can occupy each orbital is limited by the Pauli exclusion principle.
		If multiple orbitals of the same energy are available, Hund's rule says that unoccupied orbitals will be filled before occupied orbitals are reused (by electrons having different spins).
		The principle takes its name from the German Aufbauprinzip, "building-up principle", rather than being named for a scientist.
	en.wikipedia.org /wiki/Aufbau_principle (259 words)

	[No title]
		For all other atoms, electron-electron repulsions lift the degeneracy of the subshells for each value of n, and in many instances the principle quantum number is NOT the sole factor which governs the relative energy of a subshell.
		When one period of the periodic table is created by the Aufbau principle the electrons fill orbitals which are similar in energy (and hence distance from the nucleus).
		Based on electrostatic principles it makes perfect sense that these would "choose" to enter different orbitals since this maximizes their spatial separation (and hence minimizes their repulsion).
	www.research.umbc.edu /~budzicho/Chp9note5.html (1855 words)

	INTRODUCTION TO MOLECULAR MODELING
		This is a violation of the Aufbau (build-up) principle.
		It is caused by the fact that the 3d orbitals are compact, much smaller in diameter than the 4s orbitals, and therefore the electrons in the 3d orbitals repel each other strongly.
		In transition metal compounds with 4 to 7 d electrons, there is a conflict between the Aufbau (build-up) principle and Hund’s rule.
	www.uark.edu /campus-resources/pulay/Modeling05/lab9.htm (986 words)

	Electron configuration - Wikipedia, the free encyclopedia
		However, due to the Pauli exclusion principle, no more than two electrons may exist in a given atomic orbital; therefore, an electron may only leap to another orbital if there is a vacancy there.
		In the ground state of an atom (the condition in which it is ordinarily found), the electron configuration generally follows the Aufbau principle.
		The Aufbau principle can be applied, in a modified form, to the protons and neutrons in the atomic nucleus (see the shell model of nuclear physics).
	en.wikipedia.org /wiki/Electron_configuration (1329 words)

	Structure of the Atom (Site not responding. Last check: )
		The basis of this prediction is a rule known as the aufbau principle, which assumes that electrons are added to an atom, one at a time, starting with the lowest energy orbital, until all of the electrons have been placed in an appropriate orbital.
		Most of the exceptions to the electron configuration predicted from the aufbau diagram shown earlier therefore occur among elements with atomic numbers larger than 40.
		Although it is tempting to focus attention on the handful of elements that have electron configurations that differ from those predicted with the aufbau diagram, the amazing thing is that this simple diagram works for so many elements.
	chemed.chem.purdue.edu /genchem/topicreview/bp/ch6/quantumframe.html (2581 words)

	Highbeam Encyclopedia - Search Results for Aufbau
		Find newspaper and magazine articles plus images and maps related to "Aufbau" at HighBeam.
		With German Jewry Assimilated, Is it Auf Wiedersehen for Aufbau?
		Studien zur Literatur des Theravada Buddhismus, I: Entstehung und Aufbau der Jataka-Sammlung; II: Das Patimokkhasutta der Theravadin.
	www.encyclopedia.com /SearchResults.aspx?Q=Aufbau (208 words)

	Beacon Lesson Plan Library
		The student knows that elements are arranged into groups and families based on similarities in electron structure and that their physical and chemical properties can be predicted.
		It is imperative to define Aufbau Principle, Hund's Rule and Pauli Exclusion Principle before beginning this lesson so that students already have those concepts explained as far as their limited knowledge will allow.
		As soon as the first floor is explained, ask a student how many elements should be on the first floor since there is only one type of apartment and there is only one bedroom in that type of apartment.
	www.beaconlearningcenter.com /Lessons/986.htm (1680 words)

	Electronic Configurations (Site not responding. Last check: )
		The electronic configuration for the ground state of an atom can be determined by the principle of pouring sand into a bucket.
		The first grains fall to the bottom and subsequent grains fall to the lowest possible available space until all the sand is in the bucket.
		It is possible to determine the electronic configurations for the elements based on the calculated energy levels and the aufbau principle.
	home.att.net /~v.d.singleton/genchem/elconfig.htm (1353 words)

	Double-Shell PSE: Introduction
		The Aufbau (Build-up) principle of the conventional periodic system of the elements is based on the consecutive filling of the states of the hydrogen atom.
		Here a periodic system is introduced, which is of a high symmetry and is decribed by a very simple Aufbau principle, which does not require exceptions.
		By the Aufbau principle for the double-shell periodic system, the filling of a new shell starts with states of highest angular momentum of the shell and then continues with decreasing l.
	www.neubert.net /PSEIntro.html (946 words)

	Unit Outline (template)
		An electron in an atom can move from one main energy level to a higher main energy level only by absorbing an amount of energy exactly equal to the difference between the two levels.
		Electrons occupy atomic orbitals in the ground state of an atom according to the Aufbau principle, the Pauli exclusion principle, and Hund’s rule.
		State the Aufbau principle, the Pauli exclusion principle, and Hund’s rule.
	www.msu.edu /~fredenb3/main-web-pages/chemistry-sem-1/Electons_unit.htm (490 words)

	Modern Theory of Atomic Structure, page 1
		In this theory, the electron is treated as both a wave and a particle.
		The Aufbau Principle is a series of procedures that are used when placing electrons on an atom.
		As applied to elements it refers to the idea that the electronic structure of an atom is built upon the structures of all the atoms with lesser atomic numbers that occurred before it on the Periodic Chart.
	www.bcpl.net /~kdrews/mtas/modern.html (0 words)

	Chem 1 Review Problems (Site not responding. Last check: )
		Suppose that electrons have zero spin but that the Pauli exclusion principle as presented in Chemistry 1 still applies.
		Construct the periodic table and predict the ground-state electron configurations for the first 10 elements.
		That is one of the eight values can be calculated using the Bohr formula.
	pages.pomona.edu /~wsteinmetz/problems/aufbau.htm (92 words)

	Chapter 13 - Electrons in Atoms
		Explain Aufbau Principle, Hund’s Rule, and Pauli Exclusion Principle and how they are used to determine the location of an electron in an atom.
		Objectives: Apply the Aufbau principle, the Pauli Exclusion Principle, and Hund’s Rule in writing electron configurations of elements.
		According to the Aufbau principle, we know orbitals fill in order from low to high energy.
	pages.prodigy.net /anderhan/Ch13EConfig.html (6268 words)

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