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Topic: Orbital energy


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In the News (Tue 23 Apr 19)

  
  NIST: Electron-Impact Cross Section Database - Intro.
Four orbital constants--the binding energy B, the orbital kinetic energy U, the electron occupation number N, and a dipole constant Q--are needed for each orbital, and the first three constants are readily available from the ground-state wave function of the target atom or molecule.
Orbital constants obtained from the Hartree-Fock or similar wave functions are adequate.
When the energy level of the excited state is not very high compared to the lowest ionization energy, EA dominates.
physics.nist.gov /PhysRefData/Ionization/intro.html   (1250 words)

  
  Molecular Orbitals - Molecular Orbitals for Homonuclear Diatomics   (Site not responding. Last check: 2007-10-27)
Molecular orbital energy level diagram for homonuclear diatomic molecules showing the correlation of the molecular orbitals with the atomic orbitals of the separated atoms.
The nodal properties of the orbitals are indicated in Fig.
orbital for the molecule is said to correlate with the sum of 1s orbitals, one on each nucleus, for the separated atom case.
www.chemistry.mcmaster.ca /esam/Chapter_8/section_3.html   (2734 words)

  
 Atomic Orbital - nCyclopedia
An atomic orbital is the description of the behavior of an electron in an atom according to quantum mechanics.
An atomic orbital is uniquely identified by the values of the three quantum numbers, and each set of the three quantum numbers corresponds to exactly one orbital, but the quantum numbers only occur in certain combinations of values.
Generally speaking, the number n determines the size and energy of the orbital: as n increases, the size of the orbital increases.
nanotitan.com /nCyclopedia/atomicOrbital.htm   (1415 words)

  
 Sigma Bonds   (Site not responding. Last check: 2007-10-27)
When the orbitals are brought close together, two molecular orbitals are formed and these molecular orbitals are shown in the center of the diagram.
Antibonding orbitals are called "antibonding" because electrons are more stable in the atomic orbitals that overlapped to form the antibonding orbital than in the antibonding orbital itself.
For the simple overlap of two atomic orbitals, the increase in energy for the antibonding orbital is always greater (frequently much greater) than the decrease in energy for the bonding orbital.
www.chm.davidson.edu /ChemistryApplets/MolecularOrbitals/overlap/sigma.html   (771 words)

  
 SparkNotes: Atomic Structure: Atoms and Atomic Orbitals
Gives the orientation of the orbital in space; in other words, the value of m describes whether an orbital lies along the x-, y-, or z-axis on a three-dimensional graph, with the nucleus of the atom at the origin.
Orbitals with identical energies are said to be degenerate (not in the moral sense!).
Note that the energy levels in these diagrams do not follow a continuous line: an atom is either in one energy subshell or it is in another.
www.sparknotes.com /chemistry/fundamentals/atomicstructure/section1.html   (1200 words)

  
 Bohr model Summary
This excess energy is emitted in quanta of electro-magnetic radiation (photons of light) that have exactly the same energy as the difference in energy between the orbits jumped by the electron.
Additional orbital shells are assigned values n=2, n=3, n=4, etc. The orbital shells are not spaced at equal distances from the nucleus and the radius of each shell increases rapidly as the square of n.
Energy must be absorbed for an electron to move to a higher state (further from the nucleus) and emitted when the electron moves to an orbit of lower energy (closer to the nucleus).
www.bookrags.com /Bohr_model   (4442 words)

  
 Energy band Summary
When the 3s orbital of one sodium atom overlaps the 3s orbital of its immediate neighbor in a crystal lattice, two molecular orbitals are formed: a bonding orbital of lower energy and an antibonding orbital of higher energy.
In solid-state physics, an energy band is a continuous range of values of energy that an electron may or may not have.
Thus, there must be a splitting of the discrete energy levels of the isolated atoms into new energy levels belonging to the pair rather than to individual atoms.
www.bookrags.com /Energy_band   (970 words)

  
 Molecular Orbitals for Homonuclear Diatomics
The ordering of the orbital energy levels shown in the figure holds generally for all homonuclear diatomic molecules with the exception of the levels for the 1pu and 3sg orbitals, whose relative order is reversed for the molecules after C2.
A su orbital, unlike a sg orbital, possesses a node in the plane midway between the nuclei and perpendicular to the bond axis.
The attractive force exerted on the nuclei by the charge density in the sg orbitals is not sufficient to balance both the nuclear force of repulsion and the antibinding force exerted by the density in the su orbitals.
www.cartage.org.lb /en/themes/Sciences/Physics/MolecularPhysics/MolecularSpectra/Orbitals/Molecular/Molecular.htm   (2842 words)

  
 OLED-Competence > Glossary
The energy of this orbital approximates the ionization energy of the molecule.
The amount of energy required to remove an electron from a given molecule or atom to form an ion; usually expressed in units of electron volts.
The energy of this orbital is sometimes used to approximate the electron affinity of the molecule, but this usually works badly.
www.novaled.com /oledcompetence/glossary.html   (1358 words)

  
 Molecular Models
The different phases of these orbitals are colored blue and red, and are separated by nodal surfaces at which electron density is zero.
The orbital coefficients at C-2 and C-3 are greater than the coefficients at the terminal carbons.
The orbital components of higher energy pi-orbitals may be viewed by clicking appropriate buttons under the display.
www.cem.msu.edu /~reusch/VirtualText/orbitals.htm   (703 words)

  
 Organic Chemistry at Penn State: Quantum Primer III   (Site not responding. Last check: 2007-10-27)
All atoms in the molecule provide their atomic orbitals for construction of MO, but not all atomic orbitals must participate in all MO. The number of MO is equal to the number of atomic orbitals used to generate them.
The usual energy order of MO is as follows: σ-type orbitals (the lowest energy), π-type orbitals, n-type orbitals (nonbonding, such as lone pairs), π*-type orbitals and σ*-type orbitals (the highest in energy).
Since interaction between filled (occupied) orbitals does not result in net bonding (electron-electron repulsion), and interaction between empty (unoccupied) orbitals cannot contribute to bonding (no electrons to be shared) only the interaction between occupied and unoccupied will provide the initial impetus for the reorganization of existing bonding.
courses.chem.psu.edu /chem38/quantum/quantum3.html   (1337 words)

  
  February 23, 1995
We will arbitrarily set the energy at zero when the two atoms are 20A apart and we will calculate the energy of the system as the atoms approach one another to form a bond.
The key feature of this diagram is that we started with two 2s atomic orbitals each with one electron and we end up with two molecular orbitals, one of which has a pair of electrons in a lower energy, more stable configuration.
electrons, which lie higher in energy than the s electrons, will be readily excited (i.e., promoted to still higher energy levels) by light, and this property will enable us to understand the important processes such as fluorescence and the key reactions in photosynthesis.
www.uky.edu /Classes/BCH/401/Supplements/molecularorbitals.htm   (965 words)

  
 Introduction to Molecular Orbital Theory
The upper molecular orbital has a node in the electronic wave function and the electron density is low between the two positively charged nuclei.
The energy of the upper orbital is greater than that of the 1s atomic orbital, and such an orbital is called an antibonding molecular orbital.
This highest occupied orbital has a lobe pointing away from the three hydrogens, and corresponds to a lone pair orbital localized upon the nitrogen, whereas the three lowest energy MO's lead to the description of the three N-H bonds of the Lewis structure.
www.ch.ic.ac.uk /vchemlib/course/mo_theory/main.html   (2412 words)

  
 Arrangements of electrons in the orbitals of an atom is called its electron configuration.
The energy level diagram, on the left shows the relative energy of the 2s and 2p orbitals based on the ability of the sublevels to penetrate to the nucleus.
The energy required to pair the first 2s electron is less than the energy required to place the electron into the 2p orbital.
As in the case of the second level the 3s orbital is lower in energy than the 3p which is lower in energy compared to the 3d.
intro.chem.okstate.edu /1215/Lecture/Chapter11/Fri112098.html   (1484 words)

  
 Orbital Energy   (Site not responding. Last check: 2007-10-27)
The speed of the earth in orbit is 30,000 meters per second.
A kilogram of matter moving at that speed has a kinetic energy in joules equal to (1/2)*mass(kg)*(the square of the speed(m/s)) = (1/2) (1) (30,000)(30,000) = 450 million joules.
Therefore a kilogram of matter moving at the speed of the earth has as much kinetic energy as is stored in 10 kilograms of gasoline.
www.energyadvocate.com /fw43.htm   (79 words)

  
 ROCO Resonance: Energy
II is lower in energy than III (the latter improbably transfers electrons from O, a very electronegative atom, to C).
The relative energies of the resonance forms and the actual molecule (i.e., the hybrid) are shown below.
The interaction energy, Eint, between two atomic orbitals is proportional to the overlap between these orbitals.
academic.reed.edu /chemistry/ROCO/Resonance/energy.html   (1263 words)

  
 Electronic energy level changes and color
Energy transitions in phenolphthalein indicator, plant pigments, and isolated pi systems will be examined to illustrate this.
The anion imparts a color to solutions because the energy separation between the pi and pi antibonding levels is smaller and matches light in the visible range.
You will be asked to explain the different colors of the 2 chlorophylls by examining their structures and identifying the type of change in molecular orbital energy levels caused by the difference in structure.
www.800mainstreet.com /elsp/Elsp.html   (2853 words)

  
 Orbital Welding
Orbital Welding was first introduced in the late 1960's as a way to reduce the weight of hydraulic and fuel systems on commercial aircraft.
In the Pharmaceutical Industry: In the late 1970's orbital welding began to be used for Pharmaceutical water systems as a way to eliminate any contamination or areas where water may be retained for possible bacteria growth...as can happen with manual welding.
In the Semiconductor Industry: In the early 1980's with the explosion in semiconductors orbital welding was introduced as a method to improve yields through improved gas purity and leak integrity.
www.appliedenergysystems.com /orbital-welding.html   (218 words)

  
 Many-Electron Atoms - The Electronic Basis of the Periodic Table   (Site not responding. Last check: 2007-10-27)
When all the orbitals in a given shell are doubly occupied, the resulting configuration is called a "closed shell." Helium and neon are similar in that they both possess closed shell configurations.
The six elements from gallium to krypton mark the filling of the 4p orbitals and the closing, with krypton, of the fourth quantum shell and the fourth period of the table.
While the 3d orbitals are less stable than the 4s orbitals in the neutral atom (with the exceptions of Cr and Cu) and are filled only after the 4s orbitals are filled, the relative stability of the 4s and 3d orbitals is reversed in the ionic forms of the transition metals.
www.chemistry.mcmaster.ca /esam/Chapter_4/section_3.html   (2321 words)

  
 ChemViz Atomic Orbitals Lab
The s and p orbitals in a particular energy level are filled in the noble gas at the end of that period.
Notice that due to the overlap of orbitals from different energy levels, some orbitals from higher energy levels are filled before all the orbitals of previous energy levels are filled.
Try looking at atomic orbitals for other atoms besides these four and see if the shapes and energies correspond to what is expected from the electron filling chart in Figure 2.
chemviz.ncsa.uiuc.edu /content/lab-s-atomorb.html   (970 words)

  
 Approximate order of atomic orbital energy levels
The principle, formulated by the Danish physicist Niels Bohr about 1920, is an application of the laws of quantum mechanics to the properties of electrons subject to the electric field created by the positive charge on the nucleus of an atom and the negative charge on other electrons that are bound to the nucleus.
This provides enough orbitals to fill the ground states of all the atoms in the extended periodic table.
For orbitals designated as comparable in energy, e.g., 4s ~ 3d, the actual order depends which other orbitals are occupied.
www.apsidium.com /theory/levels.htm   (319 words)

  
 Energy News - Energy Technology - Energy Business - Energy and the Environment
Rooftop solar energy is a remarkably simple answer to many of America's energy problems, one of the country's leading designers and installers of solar systems documents in two white papers made public this week.
The polysilicon supplied by this agreement during the seven-year period is subject to the acceptance of product deliveries and other conditions.
The partnership is driven by the technological advantages of Terra Solar's leading status in the BIPV (building integrated photovoltaic) market place as well as the cost advantages of the product...
www.energy-daily.com   (1110 words)

  
 Duran: Chapter Twelve Molecular Orbital Theory   (Site not responding. Last check: 2007-10-27)
One of the molecular orbitals is lower in energy.
It is higher in energy than the original atomic orbitals and destabilizes the molecule.
Below is a molecular orbital energy diagram for the hydrogen molecule.
www.chem.ufl.edu /~chm2040/Notes/Chapter_12/theory.html   (706 words)

  
 Lesson 3-6 Electron Configuration
The electron configuration of an atom is a form of notation which shows how the electrons are distributed among the various atomic orbital and energy levels.
The number of sublevels that an energy level can contain is equal to the principle quantum number of that level.
Although energy levels that are higher than 4 would contain additional sublevels, these sublevels have not been named because no known atom in its ground state would have electrons that occupy them.
www.fordhamprep.org /gcurran/sho/sho/lessons/lesson36.htm   (690 words)

  
 Electron Configurations   (Site not responding. Last check: 2007-10-27)
Orbitals are filled in order of increasing energy, with no more than two electrons per orbital
Hund's rule: for degenerate orbitals, the lowest energy is attained when the number of electrons with the same spin is maximized
The 4s orbital would be filled when we have an element with 20 electrons (Calcium).
wine1.sb.fsu.edu /chm1045/notes/Struct/EConfig/Struct08.htm   (617 words)

  
 Investigating Ionization Energy Using the Atomic Explorer   (Site not responding. Last check: 2007-10-27)
Using the energy scale in the left window, determine the energy of the hydrogen electron in the ground state.
Construct a graph showing the relationship between the atomic number of the atom and the energy of the electron that would be most easily removed from that atom.
After investigating the densities of individual p orbitals of the same atom, predict the shape of the electron density when all the occupied p orbitals are selected.
www.bu.edu /smec/qsad/curriculum/text_modules/Ionization_energy.htm   (321 words)

  
 Atomic Structure
Emission spectra and orbital energy levels for hydrogen are calculated and tabularised for the stage of development to this point.
A detailed comparison of development so far with the modern quantum mechanics/quantum electrodynamics theory is also presented, together with detailed discussions on (i) emission spectra, (ii) orbital energy levels and intervals, (iii) the Lamb Shift, (iv) the mechanics of orbital transitions, and (v) ionisation orbitals.
Emission spectra and orbital energy levels for hydrogen are calculated and tabularised.
www.relativitydomains.com /Physics   (639 words)

  
 Orbital Calendrics
Beginning with the Millennium 2001 Orbital Calendar poster I include the Mayan glyphs marking their system of 18 months and 5 weeks of 4 days each, color coded as they had done.
"The Orbital Calendar Time-Space Poster is associated with a kind of subtle but powerful energy field that...displays a certain energy configuration that appears to be characteristic of places, objects and activities long considered to be sacred and powerful.
The Orbital Calendar brings the relationship personally alive and immediate on an everyday basis.
www.celestial-dynamics.com /orbital_calendrics.html   (998 words)

  
 Investigating Atomic Structure: Hund's Rule and Aufbau Principle
Electrons can occupy different orbitals in an atom, and the order of occupancy is based on the most stable arrangement.
By investigating the order in which electrons occupy the available orbitals, you will understand the characteristics of electrons and orbitals that contribute to the formation of stable atoms.
By comparing electron orbital occupancy for elements in the second period, describe the order in which electrons fill the available orbitals.
qsad.bu.edu /curriculum/text_modules/Orbital_filling_rules.htm   (514 words)

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