Download - Dr. S. M. Condren. Electromagnetic Radiation Electromagnetic wave wavelength frequency amplitude
Dr. S. M. Condren
Dr. S. M. Condren
Electromagnetic Radiation
Electromagnetic wave
• wavelength
• frequency
• amplitude
Dr. S. M. Condren
Black Body Radiation
http://www.cbu.edu/~mcondren/C11599/BBvis.mov
Dr. S. M. Condren
Photoelectric Effect
• the emission of electrons by substances, especially metals, when light falls on their surfaces.
Dr. S. M. Condren
Dr. S. M. Condren
Dr. S. M. Condren
Line Spectrum
A spectrum produced by a luminous gas or vapor and appearing as distinct lines characteristic of the various elements constituting the gas.
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.
Dr. S. M. Condren
Ground State
The state of least possible energy in a physical system, as of elementary particles. Also called ground level.
Dr. S. M. Condren
Excited State
Being at an energy level higher than the ground state.
Dr. S. M. Condren
Dr. S. M. Condren
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
Dr. S. M. Condren
Bohr Atom
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
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
Dr. S. M. Condren
paramagnetic ferromagnetic
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
Zeff = Z - Swhere Zeff => effective nuclear charge
Z => nuclear charge, atomic numberS => shielding constant
Dr. S. M. Condren
Dr. S. M. Condren
Dr. S. M. Condren
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
Dr. S. M. Condren
Dr. S. M. Condren
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”