HSTMr.Watson Chapter 7 Quantum Theory of the Atom

HSTMr.Watson Electromagnetic Radiation Electromagnetic wave A wave of energy having a frequency within the electromagnetic spectrum and propagated as a periodic disturbance of the electromagnetic field when an electric charge oscillates or accelerates.

HSTMr.Watson Electromagnetic Radiation Electromagnetic wave wavelength frequency amplitude

HSTMr.Watson Electromagnetic Radiation = c where  => frequency  => wavelength c => speed of light

HSTMr.Watson Wave Nature of the Electron

HSTMr.Watson Electromagnetic Spectrum

HSTMr.Watson Line Emission Spectrum

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

HSTMr.Watson 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.

HSTMr.Watson Ground State The state of least possible energy in a physical system, as of elementary particles. Also called ground level.

HSTMr.Watson Excited State Being at an energy level higher than the ground state.

HSTMr.Watson Photoelectric Effect the emission of electrons by substances, especially metals, when light falls on their surfaces.

HSTMr.Watson Photoelectric Effect

HSTMr.Watson Quantum Mechanics Quantum theory the theory of the structure and behavior of atoms and molecules.

HSTMr.Watson Black Body Radiation

HSTMr.Watson Electromagnetic Radiation E hi - E lo = hc/ where E => energy h => Planck's constant c => speed of light  => wavelength

HSTMr.Watson Photons The quantum of electromagnetic energy, generally regarded as a discrete particle having zero mass, no electric charge, and an indefinitely long lifetime.

HSTMr.Watson Dispersion of White Light

HSTMr.Watson The Atomic Spectrum of Hydrogen and the Bohr Model Bohr Model for the Hydrogen Atom mnr = nh/2p

HSTMr.Watson Bohr Atom

HSTMr.Watson Bohr Model E = -B/n 2 where n => quantum number 1, 2, 3, 4, 5, 6, 7, etc

HSTMr.Watson Bohr Model for hydrogen ground state: n = 1 excited state: n > 1

HSTMr.Watson Bohr Model E = ( X J/part.) (6.022 X part./mole) (1 kJ/10 3 J)/n 2 = (-1312 kJ/mol)(1/n 2 )

HSTMr.Watson Electron Transition in a Hydrogen Atom Lyman series => ultraviolet n > 1 ==> n = 1 Balmer series => visible light n > 2 ==> n = 2 Paschen series => infrared n > 3 ==> n = 3

HSTMr.Watson Line Spectra See CHEMWORKS software

HSTMr.Watson 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

HSTMr.Watson Knowing diamond is transparent, which curve best represents the absorption spectrum of diamond (see below)? A, B, C

HSTMr.Watson According to the energy diagram below for the Bohr model of the hydrogen atom, if an electron jumps from E1 to E2, energy is absorbed emitted not involved

HSTMr.Watson Heisenberg, Werner 1901–76, German physicist 1932 Nobel Prize in physics A founder of QUANTUM MECHANICS, he is famous for his uncertainty principle, which states that it is impossible to determine both the position and momentum of a subatomic particle (such as the electron) with arbitrarily high accuracy.

HSTMr.Watson Heissenberg Uncertainty Principle “ it is impossible to determine both the position and momentum of a subatomic particle (such as the electron) with arbitrarily high accuracy” The effect of this principle is to convert the laws of physics into statements about relative, instead of absolute, certainties.

HSTMr.Watson Orbitals region of probability of finding an electron around the nucleus 4 types => s p d f maximum of 2 electrons per orbital

HSTMr.Watson Pure Atomic Orbitals shape # of orbitals / energy level s spherical 1 p dumbbell 3 d complex 5 f very complex 7

HSTMr.Watson Atomic Orbitals, s-type

HSTMr.Watson Atomic Orbitals, p- type

HSTMr.Watson Atomic Orbitals, d-type

HSTMr.Watson Atomic Orbitals, f-type

HSTMr.Watson Shapes of Orbitals