Due: Energy Calculations - compare Take out Periodic Table Today: 1. Quantum Theory 2. First Quantum Numbers (n, l) HW p ; p

Due: Lab Notebooks Take out Periodic Table Today: 1. Quantum Numbers m & sQuantum Numbers HW ; p , 24, 25

General Chemistry

 Heisenberg, Schrodinger, many others, ~1926  Think atom is mostly empty space  Nucleus in center is dense, positively charge  Electrons  Cannot locate  The new idea: The chemical properties of atoms, ions, compounds, and molecules are attributed to the arrangement of the electrons Also called “The Electron Cloud”

Heisenberg Uncertainty Principle You can find out where the electron is, but not where it is going. OR… You can find out where the electron is going, but not where it is! “One cannot simultaneously determine both the position and momentum of an electron.” WernerHeisenberg

 Ĥ Ψ = E Ψ predicts the position and energy of an electron in an atom.  ** Ψ is a function of the electrons position in three dimensional space.  Ĥ is an operator designating the total energy of the atom.  These wave functions correspond to the different orbitals that the electrons may occupy.  Schrodinger’s Cat Schrodinger’s Cat

 The model gives us no information about the exact position or momentum of the electrons in an atom.  An orbital provides us with a three dimensional shape encompassing where the electron will be 90% of the time.  If the probability is greater for the space around the nucleus then it looks fuzzyfuzzy, because the area is more dense

 Each orbital has a unique probability distribution and shape.  Each orbital represents the surface that surrounds 90% of the total electron probability.  Areas of zero probability between orbitals are called nodes.  Described by 4 Quantum Numbers n, l, m, s

 Corresponds to the major energy level in an atom  Determines the volume of the electron cloud  Assign values of increasing energy  As you increase n you increase the average distance that the electron is to the nucleus, and an increase in energy  Value of n = 1, n = 2, n = 3... n = 7 1

 There is a maximum number of electrons that can be found for each Energy level  Use equation 2(n) 2  Where n is the energy level being discussed  Level (n)max # of electrons

 Describes the shape of the orbitals s, p, d & f  Number of sublevels each principal quantum number has is dependent upon the integer it is assigned Level (n) # of sublevels Names of sublevels 11 1s1s1s1s 22 2s & 2p 33 3s, 3p, 3d 44 4s, 4p, 4d, 4f

 They are spherical in shape.  The radius of the sphere increases with the value of n.  1 variation  S means “sharp”

 They have two lobes with a node between them.  Dumbbell shape  3 variations  p means principal

Four of the five d orbitals have 4 lobes; the other resembles a p orbital with a doughnut around the center. Four of the five d orbitals have 4 lobes; the other resembles a p orbital with a doughnut around the center. 5 variations 5 variations d means diffuse d means diffuse

 7 variations  f means fundamental

 The magnetic quantum number, m l, is related to each orbital’s orientation in space with respect to the other orbitals.  ** only 2 electrons can fill each individual orbital, but the p sublevel can have 6 electrons

Energy Levels, Orbitals, Electrons

 In the 1920s, it was discovered that two electrons in the same orbital do not have exactly the same energy.  The “spin” of an electron describes its magnetic field, which affects its energy.  This led to a fourth quantum number, the spin quantum number, m s.