What things were wrong with Bohr’s atomic model? L. Bernard, 2016

The Electron Chapter 5 L. Bernard, 2016

Revising the Atomic Model 5.1 L. Bernard, 2016

What’s wrong with Bohr’s model? Electrons don’t move in perfect circles! What did Louis de Broglie say electrons behaved like? Energy levels have sub-levels L. Bernard, 2016

The Quantum Mechanical Model Does not specify the path an electron takes around the nucleus Heisenberg Uncertainty Principle What is the probability of an electron being in a certain place at a certain time? L. Bernard, 2016

The Quantum Mechanical Model Each energy level can be broken down into sublevels Sublevels are denoted by letter Each of those sublevels has a unique amount of orbitals These orbitals describe where the electron is most likely to be found L. Bernard, 2016

Atomic Orbitals Four different types of sublevel s, p, d, f L. Bernard, 2016

Atomic Orbitals s – 1 orbital p – 3 orbitals d – 5 orbitals f – 7 orbitals Each orbital can hold at maximum two electrons L. Bernard, 2016

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How do we know where electrons go within these sublevels and their orbitals? Aufbau Diagram L. Bernard, 2016

How do we know where electrons go within these sublevels and their orbitals? Orbital Filling Diagrams L. Bernard, 2016

Filling in these diagrams Depict electrons as arrows Can only put TWO arrows in each orbital box One pointing up, one pointing down The direction of the arrow shows which way the electron is spinning L. Bernard, 2016

Three rules to filling out Aufbau diagrams and orbital filling diagrams Aufbau Principle Electrons occupy the orbitals of lowest energy first In other words, fill 1s in completely before you fill in 2s Pauli Exclusion Principle An orbital can have at maximum two electrons Those electrons must have opposite spin Hund’s Rule Maximize the spin of the sublevel In other words, put one electron in every orbital pointing up before filling the orbitals completely L. Bernard, 2016

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Practice! What does the Aufbau diagram for Carbon look like? L. Bernard, 2016

Practice! What does the Aufbau diagram for Neon look like? L. Bernard, 2016

Practice! What does the Aufbau diagram for Calcium look like? L. Bernard, 2016

Is there an easier way to write these out? L. Bernard, 2016

Electron Configuration Condensed, shorthand version of an Aufbau diagram Simply write out the name of the sublevel with the number of electrons in that sublevel subscripted L. Bernard, 2016