Atomic Spectra and Bohr Atom 5 4 3 2 1 1 R 1 n12 1 n22 R 1 097E7 m 1 n1 n 2 Which electronic transition of hydrogen would you expect to occur in the visible range of electromagnetic radiation A n1 1 to n2 2 B n1 1 to n2 3 C n1 2 n2 3 D n1 4 to n2 5E depends on the value of Planck s constant Electrons are both particles and waves Wave Nature of the Electron Louis de Broglie h mv ConceptTest Usain Bolt may be the fastest human with a speed of 23 mph 10 3 m s He weighs 94 kg What is his deBroglie wavelength at that speed h 6 626E 34 Js J kg m2s 2 A 6 84E 37 m Quantum Numbers Review Principal quantum number n 1 2 3 4 shells rows in periodic table Angular momentum quantum number l 0 1 2 n 1 OR l s p d f g h n 1 definite shapes Magnetic quantum number ml l l 1 0 l 1 l o l 0 s orbital ml 0 only 1 value o l 1 p orbital ml 1 0 1 3 p orbitals x y z o l 2 d orbitals ml 2 1 0 1 2 5 shapes directions o l 3 f orbitals ml 3 2 1 0 1 2 3 7 shapes directions Spin quantum number ms or spin parallel antiparallel ConcepTest What are the values of n l and m for a 4s orbital C 4 0 0 Quantum numbers Spin QN Fourth value spin quantum number ms o Two possible values or o Spin orientation Rules o Pauli exclusion principle Electron Spin ElectronOccupancy Spins describe direction of electron s magnetic field o Simple description up down v Paramagnetic atoms unpaired electrons Diamagnetic atoms paired electrons v Most atoms are diamagnetic orbitals have 2 paired elecrons of orbitals per n level n2 number e 2n2 Paramagnetism net field in external magnetic field Diamagnetism no net magnetic field Ferromagnetism permanent magnetic field