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52 Cards in this Set
- Front
- Back
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What is electronic structure? |
-The arrangement and energy of electrons in an atom -helps us understand the periodic table -refers to the number of electrons in the atom as well as their distribution around the nucleus and their energies |
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What is electromagnetic radiation? (EM radiation) |
-Any wave that oscillates -it is energy released by certain electromagnetic processes |
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Waves move at the |
Speed of light (c) 3.00 X 10^8m/s |
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Transverse waves |
Move up and down |
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Longitudinal |
Are parallel waves |
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Electromagnetic spectrum |
A display of electromagnetic radiation in increasing order |
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Wavelength |
The distance between 2 adjacent peaks -lambda |
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Units of wavelength |
Angstorm,nanometer,micrometer,mm,cm,m,km |
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What is frequency |
The number of complete wavelengths that pass a given point each second
-nu=frequency |
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Units of frequency |
Cycles per second, hertz per second |
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Relationship of wavelength and frequency |
They are inversely proportional |
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C= |
Lambda times nu (Wavelength times frequency ) |
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Nature of energy-quanta |
Max Planck assumed energy comes in packets called quanta |
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The photoelectric effect |
-Einstein used quanta to explain this -light hitting a metal surface causes electrons to be emitted from the surface of the metal -each metal has a diff minimum energy at which it ejects electrons |
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Photons |
Tiny energy particles |
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Each photon can have |
Particle and wave like prop |
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Einstein found that |
Energy is proportional to frequency
E=hv H=Plancks constant |
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Planks constant |
6.626X10^-34 J/s |
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For atoms and molecules you do not see a |
Continuous spectrum
-only see a line spectrum of discrete wavelength -each element has a unique line spectrum |
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Johann Balmer |
Discovered formula relating four lines to intergers |
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Johannes rydberg |
Advanced johann balmers formula
1/wavelenth =(RH)(1/n21-1/n22)
Neil's bohr explained why worked |
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Neil's Bohr adopted planks assumption and explained |
1-electrons in an atom can only occupy certain orbits(corresponding to certain energies) 2-electrons in permitted orbits have specific allowed energies-energies will NOT be radiated from the atom 3-energy is absorbed or emitted in such a way to as to MOVE an electron from one ALLOWED state to another
E=hv |
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Limitations of Bohr model |
1-only works for hydrogen 2-circular motion is not wave like in nature |
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Ideas from Bohr model |
-electrons exist only in certain discrete energy levels -energy is involved in the transition of an electron from one level to another |
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The wave nature of matter |
LOUIS DE BROGLIE theorizes that if light can have material prop, then matter should display wave prop
Wavelength=h ----- mv (mass and frequency) |
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The uncertainty principle |
-Heisenberg showed that the more precisely the momentum of a particle is known, the less precisely is its position known |
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Quantum mechanics |
Erwin schrodinger-developed a math. Treatment into which both the wave and particle nature of matter could be incorporated The square of the wave equation gives the electron density or probability of where an electron is likely to be at any given time |
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Quantum numbers |
Solving wave equation gives set of wave functions or orbitals and their corresponding energies Each orbital describes a spatial distribution of electron density An orbital is described by a set of 3 quantum numbers |
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Principle quantum number (n) |
Described the energy level on which the orbital resides The values of n are integers greater than or equal to 1 Correspsonds to values in the Bohr model |
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Angular momentum quantum number (l) |
Defines shape of orbital Values of l are integers ranging from 0 to n-1 We use letter designations to communicate the different values of 1 and the shapes and types of orbitals |
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Angular momentum quatumb number (l) |
Value of l 0. 1. 2. 3 Letter used s p. d. f |
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Angular momentum quatumb number (l) |
Value of l 0. 1. 2. 3 Letter used s p. d. f |
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Magnetic quantum number (m1) |
Describes the 3D orientation of the orbital Allowed values are intergers ranging from -l to l: -l is less than or equal to m is less than or equal to l On any energy level there can be up to 1 s orbital, 3 p orbitals, 5 d orbitals, 7 f orbitals, so on |
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Angular momentum quatumb number (l) |
Value of l 0. 1. 2. 3 Letter used s p. d. f |
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Pauli exclusion principle |
-no two electrons in the same atom can have the exact same energy -no two electrons in the same atom can have identical sets of quantum numbers -this means that every electron in an atom must differ by at least one of the four quantum number values: n,l,m1, ms |
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Electron configurations |
The way electrons are distributed in an atom |
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The most stable organization is the lowest possible energy -each component consists of A) a number denoting the energy level B) a letter denoting the type of orbital C) a superscript denoting the number of electrons in those orbitals |
Ground state |
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Orbital diagrams |
Back (Definition) |
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Hund's rule |
For degenerate orbitals, the lowest energy is attained when the number of electrons with the same spin is maximized -means that for a set of orbitals in the sub level, there must be one electron in each orbital before pairing and the electrons have the same spin |
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Condensed electron configuration |
Elements in the same group of the periodic table have the same number of electrons in the outer most shell-called valence electrons
The inner shell electrons are called core electrons-these include completely filled d or f sub levels
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Valence electrons |
Back (Definition) |
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Periodic table |
-we fill orbitals in increasing order of energy -dif blocks on the PT correspsong to different types of orbitals s= blue p=pink d=orange( transition) f=tan(lanthanides, actinides or inner transition elements)
Some irregularities occur when there are enough electrons to half-fill s and d orbitals on a given row |
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Done |
Done |
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Magnetic quantum number (m1) |
Describes the 3D orientation of the orbital Allowed values are intergers ranging from -l to l: -l is less than or equal to m is less than or equal to l On any energy level there can be up to 1 s orbital, 3 p orbitals, 5 d orbitals, 7 f orbitals, so on |
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Magnetic quantum number (m1) |
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S orbitals |
-the value of l for s orbitals is 0 -they are spherical in shape -the radius of the sphere increases with the value of n -for an ns orbital, the number of peaks is n -for an ns orbital, the number of nodes(where there is 0 probability of finding an electron) is n-1 -Adan increases, the electron density is more spread out and there is a greater chance of finding an electron further from the nucleus |
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P orbitals |
-the value of l for p orbitals is 1 -they have two lives with a node between them |
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D orbitals |
The value of l for a d orbital is 2 Four of the five d orbitals have four lobes; the other resembles a p orbital with a doughnut around the center |
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F orbitals |
Very complex shapes Seven equivalent orbitals in a sub level l=3 |
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Energies of orbitals-hydrogen |
For a one electron hydrogen atom, orbitals on the same energy level have the same energy Chemists cal them degenerate orbitals |
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Energies of orbitals- many electron atoms |
As the number of electrons increases, so dos the repulsion between them In atoms with more than one electron, not all orbitals on the same energy level are degenerate Orbital sets in the same sub level are still degenerate Energy levels start to overlap in energy |
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Spin quantum number , ms |
-two electrons in the same orbitals do not have exactly the same energy -the spin of an electron describes its magnetic field-which affects the energy -the spin quantum number only has two allowed values- +1/2 and -1/2 |
