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Dr. S. M. Condren. Electromagnetic Radiation Electromagnetic wave wavelength frequency amplitude.

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Presentation on theme: "Dr. S. M. Condren. Electromagnetic Radiation Electromagnetic wave wavelength frequency amplitude."— Presentation transcript:

1 Dr. S. M. Condren

2 Electromagnetic Radiation Electromagnetic wave wavelength frequency amplitude

3 Dr. S. M. Condren Black Body Radiation http://www.cbu.edu/~mcondren/C11599/BBvis.mov

4 Dr. S. M. Condren Photoelectric Effect the emission of electrons by substances, especially metals, when light falls on their surfaces.

5 Dr. S. M. Condren

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7 Line Spectrum A spectrum produced by a luminous gas or vapor and appearing as distinct lines characteristic of the various elements constituting the gas.

8 Dr. S. M. Condren Emission Spectrum The spectrum of bright lines, bands, or continuous radiation characteristic of and determined by a specific emitting substance subjected to a specific kind of excitation.

9 Dr. S. M. Condren Ground State The state of least possible energy in a physical system, as of elementary particles. Also called ground level.

10 Dr. S. M. Condren Excited State Being at an energy level higher than the ground state.

11 Dr. S. M. Condren

12 Absorption Spectrum Light shinning on a sample causes electrons to be excited from the ground state to an excited state wavelengths of that energy are removed from transmitted spectra

13 Dr. S. M. Condren Bohr Atom

14 Dr. S. M. Condren Line Spectra Lyman series => ultraviolet n > 1 ==> n = 1 Balmer series => visible light n > 2 ==> n = 2 Paschen series => infrared n > 3 ==> n = 3

15 Dr. S. M. Condren Magnetism Result of the spin of electrons diamagnetism - no unpaired electrons paramagnetism - one or more unpaired electrons ferromagentism - case of paramagnetism where the substance retains its magnetism

16 Dr. S. M. Condren paramagnetic ferromagnetic

17 Dr. S. M. Condren Atomic Radius increase top to bottom down a group –each additional electron “shell” shields the outer electrons from the nuclear charge Z eff = Z - S whereZ eff => effective nuclear charge Z => nuclear charge, atomic number S => shielding constant

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20 Ionization Energy energy necessary to remove an electron to form a positive ion low value for metals, electrons easily removed high value for non-metals, electrons difficult to remove increases from lower left corner of periodic table to the upper right corner

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22 Electron Affinity energy released when an electron is added to an atom same trends as ionization energy, increases from lower left corner to the upper right corner metals have low “EA” nonmetals have high “EA”


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