Lecture 6: Sub-atomic & quantum structure Lecture 6 Topics: Brown, chapter 6 & 7 1. Atomic properties from e- configuration 7.1 2. The true nature of the atom? 6.1 Light (and electrons) behave as waves & particles 3. Developing a new physics for atoms 6.2 – 6.4 A quick tour of quantum mechanics 4. Bohr’s quantum planetary model 6.2 5. Applying quantum mechanics to the atom Electrons inhabit orbitals 6.6 – 6.7 6. Orbital filling and electron configuration 6.8 – 6.9 Aufbau & orbital diagrams

Properties of atoms result from electron configuration Elements in each column have the same configuration. The general process of advancing scientific knowledge by making experimental observations and by formulating hypotheses, theories, and laws. It’s a systematic problems solving process AND it’s hands-on….. Experiments must be done, data generated, conclusions made. This method is “iterative”; it requires looping back and starting over if needed. [Why do you think they call it REsearch?] Often years, decades or more of experiments are required to prove a theory. While it’s possible to prove a hypothesis wrong, it’s actually NOT possible to absolutely prove a hypothesis correct as the outcome may have had a cause that the scientist hasn’t considered.

Atomic properties & electron configuration The physical & chemical properties of each element are a result of the arrangement of the electrons of an atom around its nucleus. Number of electrons dictates how they are “configured” around the atoms nucleus. The configuration of electrons is dictated by their energy levels. The outermost shell of electrons (the valance shell) bonds to other atoms. Columns: atoms with the same valance shell configuration Similar physical & chemical properties. Rows (periods): atoms with the same number of electron shells First pages of Ch 7

The beauty of the periodic table Mendeleev, creator of the table, predicted the nature of elements not yet discovered by relating their properties to those of adjacent and well characterized elements. First pages of Ch 7

Examples: periodic table knowledge Which have the most similar physical & chemical characteristics? B, Ca, F, He, Mg, P Of the elements listed only Ca & Mg are found in the same column. Elements found in the same column have the most similar properties. Find sodium & bromine in the table. a) Give the atomic number of each. b) Label each as a metal, nonmetal, or metalloid. Na is in column IA; number 11 & a metal. Br is in column VIIA; number 35 & a nonmetal. Metals Metalloids Nonmetals West Coast - luster, conduct heat & electricity, solids (except Hg) Staircase that separates metals & nons. Properties lie between metals & nons. Great Lakes & East Coast - Properties are non-metallic. Can be gases, liquids or solids at room temp. First pages of Ch 7