CHEM 1211 Lecture 16 Outline of Last Lecture I Electromagnetic Radiation A Emission Spectrum B Absorption Spectrum C Bohr Model of Atom II Predicting Emission Lines of Hydrogen A Rydberg Equation III Electronic Transitions A Wave nature of electrons Outline of Current Lecture I Orbital Quantum Number 1 Clicker Question One 2 Clicker Question Two 3 Clicker Question Three A The S Orbital B The P Orbital C The D Orbital II Spin Quantum Number 1 Clicker Question Four Current Lecture I Orbital Quantum Number An atomic orbital is defined by three quantum numbers N shell principle L Angular Momentum Quantum Number Ml Designates an orbital within a shell Electrons arranged in shells and subshells made of orbitals You cannot figure out Ml without L or L without N 1 Clicker Question One Calculate Enthalpy H f for H2S g given that Enthalpy H fO2 0 KJ mol Enthalpy H fSO2 296 8 KJ mol Enthalpy H fH2O 285 8 KJ mol Enthalpy H 298 1124 KJ mol Answer 20 6 KJ 2 Clicker Question Two Which is not a possible value for the principle quantum number A 4 B 2 C 1200 D 0 3 Clicker Question Three Consider the third shell in Hydrogen How many values of the angular momentum quantum number would be possible A 0 B 1 C 2 D 3 E 4 A The S Orbital The 1st shell has n 1 lowest energy SO l 0 ml 0 Since ml has a single value the subshell has a single orbital This subshell is labeled S and we call this orbital 1S it has a spherical shape State with the lowest energy state first when dealing with electrons B The P Orbital For n 2 l 0 and 1 II Two types of orbitals 2 subshells For l 0 ml 1 0 1 this is the p subshell with three orbitals When l 1 there is a planar node through the nucleus Planar node spot on orbital where the probability of find the electron is zero Px Py Pz Degenerate have same energy C The D Orbital third shell 2 planar nodes For l 2 ml 2 1 0 1 2 D subshell with five orbitals Number of nodes value of angular quantum number l There are n2 orbitals in the nth shell Spin Quantum Number Last Quantum number is the spin quantum number Ms The spin quantum number values Ms 1 2 or 1 2 Quantum number tells us the spin and orientation of the magnetic field of the electron Wolfgang Pauli 1925 Exclusion Principle NO two electrons in an atom can have the same set of four quantum numbers Orbitals can only have two electrons max Doesn t have to have two electrons though 1 Clicker Question Four Which of these subshell types isn t possible A 5s n 5 l 0 B 4p n 4 l 1 C 3d n 3 l 2 D 2d n 2 l 2 E 2p n 2 l 1
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