05+Electron+Configuration


 * **__Chapter 5 Section I: Models of the Atom__**
 * What was inadequate about Rutherford's atomic model?
 * What was the new proposal in the Bohr model of the atom?
 * What does the quantum mechanical model determine about the electrons in an atom?
 * How do sublevels of principal energy levels differ?


 * __Chapter 5 Section II: Electron Arrangement in Atoms__**
 * What are the three rules for writing the electron configurations of elements?
 * Why do actual electron configurations for some elements differ from those assigned using the aufbau principle?


 * __Chapter 5 Section III: Physicas and the Quantum Mechanical Model__**
 * How are the wavelength and frequency of light related?
 * What causes atomic emission spectra?
 * How are the frequencies of light an atom emits related to changes of electron energies?
 * How does quantum mechanics differ from classical mechanics?



=**Outlined Notes**= A. The Development of Atomic Models - 1. Rutherford's atomic model could not explain the chemical properties of elements - a. His model was known as the planetary or nuclear atom model B. The Bohr Model - 1. Niels Bohr (1885-1962) was a Danish physicist and a student on Rutherford - 2. Bohr proposed that an electron is found only in specific circular paths, or orbits, around the nucleus in 1913 - a. Model is known as the orbital model - 3. The fixed energies electrons can have are energy levels - 4. In general, the higher and electron is on the energy ladder, the farther it is from the nucleus - 5. A quantum of energy required to move an electron from one energy level to another - 6. The higher energy levels are closer together C. The Quantum Mechanical Model - 1. In 1926, Austrian physicist Erwin Schrödinger (1887-1961) used Rutherford's and Bohr's models to create an equation describing the behavior of - the electron in a hydrogen atom - 2. The quantum mechanical model and the electron cloud model come from mathematical solutions to the Schrödinger equation - 3. The quantum mechanical model determines the allowed energies an electron can have and how likely it is to find the electron in various locations - around the nucleus - 4. Model describes how the movement of the electron around the nucleus is similar to the motion of a rotating propeller blade D. Atomic Orbitals - 1. An atomic orbital is often thought of as a region of space in which there is a high probability of finding an electron - 2. Each energy sublevel corresponds to an orbital of different shape which likely describes where the electron is likely to be found
 * __Chapter 5 Section I: Models of the Atom__**

A. Electron Configurations --- 1. __Electron configurations__ - the ways in which electrons are arranged in various orbitals around the nuclei of atoms --- 2. Three rules tell you how to find the electron configurations of atoms -- a. Aufbau Principle -- · The electrons occupy the orbitals of the lowest energy first -- b. Pauli Exclusion Principle -- · An atomic orbital may describe at most 2 electrons -- · To occupy the same orbital, 2 electrons must have opposite -- spins; that is, the electron spins must be paired -- c. Hund’s Rule -- · States that electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible B. Exceptional Electron Configurations --- 1. Filled energy sublevels are more stable that partially filled sublevels --- 2. Some actual electron configurations differ from those assigned using the aufbau principle because half-filled sublevels are not as stable as filled sublevels, but they are more stable that other configurations
 * __Chapter 5 Section 2: Electron Arrangements in Atoms__ **

A. Light --- 1. By 1900, there was enough experimental evidence to convince scientists that light consists of waves. --- 2. Each complete wave cycle starts at zero, increases to its highest value, passes through zero to reach its lowest value, and returns to zero again. --- 3. __Amplitude__ – the wave’s height from 0 to crest --- 4. __Wavelength__ – represented by λ (the Greek letter //lambda// ); is the distance between crests --- 5. __Frequency__ – represented by ν (the Greek letter //nu// ); is the number of wave cycles to pass a given point per unit of time --- 6. Units of frequency = Hertz (H2) (Can also be written as a reciprocal second) --- 7. The product of frequency and wavelength always equal a constant (c), the speed of light --- 8. The wavelength and frequency of light are inversely proportional to each other (wavelength increases, frequency decreases) --- 9. __Electromagnetic radiation__ – includes radio waves, microwaves, infrared rays, visible light, x-rays, and gamma rays --- 10. When sunlight passes through a prism, the different frequencies separate into a spectrum of colors (ex. A rainbow) B. Atomic Spectra --- 1. When atoms absorb energy, electrons move into higher energy levels. They loose energy by emitting light when they return to lower energy levels. --- 2. When light passes through the prism, the frequencies of light emitted by an element separate into discrete lines to give to give the __atomic emission spectrum__ of the element. --- 3. No two elements have the same emission spectrum C. An Explanation of Atomic Spectra --- 1. __Ground state__ – when the electron has its lowest possible energy (in ground state, principle quantum #(n) is 1 --- 2. This quantum of energy E is related to the frequency ν of the light emitted by the equation E = h× ν where h is equal to 6.626×10-34j×s --- 3. The light emitted by an electron moving from a higher to a lower energy level has a frequency directly proportional to the energy change of the electron. --- 4. Bohr’s theory was only partially satisfactory --- a. It explained the emission spectrum of hydrogen but not the emission spectra of atoms with more than one electron D. Quantum Mechanics --- 1. __Photons__ – light quanta --- 2. 1924 – French graduate student Louis de Broglie (1892-1987) asked ‘Given that light behaves as waves and particles, can particles of matter behave as waves?’ (he was later awarded the Nobel Peace Prize) --- 3. De Broglie’s equation predicts that all moving objects have wavelike behavior --- 4. Classical mechanics adequately describes the motions of bodies much larger that atoms, while quantum mechanics describes the motions of subatomic particles and atoms of waves. --- 5. German physicist Werner Heisenberg – The Heisenberg Uncertainty Principle states that it is impossible to know exactly both the velocity and the position of a particle at the same time --- 6. The discovery of matter waves paved the way for Schrödinger's quantum mechanical description of electrons in atoms
 * __Chapter 5 Section 3: Physics and the Quantum Mechanical Model__ **

=**Reference Pages**=

==Electromagnetic Spectrum

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 * ** Table 3-6a - Orbital and Electron Capacity for the Four Named Sublevels ** ||
 * **Sublevel** || **# of orbitals** || **Maximum number of electrons** ||
 * **s** || **1** || **2** ||
 * **p** || **3** || **6** ||
 * **d** || **5** || **10** ||
 * **f** || **7** || **14** ||


 * ** Table 3-6b Orbitals and Electron Capacity of the First Four Principle Energy Levels ** ||
 * **Principle energy level (n)** || **Type of sublevel** || **Number of orbitals per type** || **Number of orbitals per level(n2)** || **Maximum number of electrons (2n2)** ||
 * **1** || **s** || **1** || **1** || **2** ||
 * **2** || **s** || **1** || **4** || **8** ||
 * ^  || **p** || **3** ||^   ||^   ||
 * **3** || **s** || **1** || **9** || **18** ||
 * ^  || **p** || **3** ||^   ||^   ||
 * ^  || **d** || **5** ||^   ||^   ||
 * **4** || **s** || **1** || **16** || **32** ||
 * ^  || **p** || **3** ||^   ||^   ||
 * ^  || **d** || **5** ||^   ||^   ||
 * ^  || **f** || **7** ||^   ||^   ||
 * [[image:http://www.opencollege.com/simsim/php/ResourceManager.php?cmd=get_ss&catID=1526 width="521" height="521" caption="external image"]] ||
 * external image ||

=**Practice Problems**=

1. Which of the following is the correct electron configuration for the bromide ion, Br-?
[|a)][Ar] 4s24p5 [|b)][Ar] 4s23d104p5 [|c)][Ar] 4s23d104p6 [|d)][Ar] 4s23d104p65s1 [|e)][Ar] 4s23d103p6

**2. Which of the following elements has the largest number of electrons for which the principal quantum number, n, is 3?**
[|a) Na] [|b) Al] [|c) Si] [|d) Cl] [|e) Ar] [|f) Zn]

3. Which is the first element to have 4d electrons in its electron configuration? [|a) Ca] [|b) Sc] [|c) Rb] [|d) Y] [|e) La]

=**Assignments**=

=**Labs**=
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=**Sample Test**= [|http://www.quia.com/quiz/730529.html] [|http://lrc-srvr.mps.ohio-state.edu/shell-cgi/world/genquiz.pl] [|http://www.quia.com/quiz/730529.html?AP_rand=1766259986] [|http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch6/electronconfigpractice.html] [|http://library.thinkquest.org/17658/learn/econfigquiz.html] [|http://www.geocities.com/junebug_sophia/electronconfigquiz.htm] [|http://www.mp-docker.demon.co.uk/as_a2/topics/electronic_configurations/quiz_1.html] [|http://www.mp-docker.demon.co.uk/as_a2/topics/electronic_configurations/quiz_2.html] [|http://www.mp-docker.demon.co.uk/as_a2/topics/electronic_configurations/quiz_3.html] [|http://www.mp-docker.demon.co.uk/as_a2/topics/electronic_configurations/quiz_4.html] [|http://www.mp-docker.demon.co.uk/as_a2/topics/electronic_configurations/quiz_5.html] [|http://lrc-srvr.mps.ohio-state.edu/shell-cgi/world/genquiz.pl] [|http://www.chem4kids.com/files/atom_orbital.html] [|http://www.geocities.com/junebug_sophia/electronconfigquiz.htm] [|http://www.mcwdn.org/chemist/atom/atomquiz.html] == [|http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson36.htm] [|http://library.thinkquest.org/10429/low/eleconfig/electron.htm] [|http://www.mpcfaculty.net/mark_bishop/complete_electron_configuration_help.htm] [|http://www.csun.edu/~psk17793/G%20Chemistry/electron_configurations.htm] [|http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch6/quantum.html] [|http://www.mikeblaber.org/oldwine/chm1045/notes/Struct/EConfig/Struct08.htm] [|http://intro.chem.okstate.edu/WorkshopFolder/Electronconfnew.html] [|http://www.answers.com/topic/electron-configuration] __[|http://chemistry.about.com/od/electronicstructure/ss/aufbau_4.htm] [|http://hyperphysics.phy-astr.gsu.edu/hbase/pertab/perlewis.html] [|http://www.science.co.il/PTelements.asp?s=Group] [|http://www.wikihow.com/Write-Electron-Configurations-for-Atoms-of-Any-Element] []__