Lecture 6 NotesThe Periodic Table and Atomic Configurations Notes

Lecture 6 NotesThe Periodic Table and Atomic Configurations Notes

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The Periodic Table and Atomic Configurations Notes B. A. Rowland 53750/53760 History of the Periodic Table The current version of the Periodic Table was organized by Dmitri Mendeleev in 1869. He arranged his version of the Periodic Table by atomic mass (rather than by atomic number as we do now). His Periodic Table allowed him to make several corrections to atomic masses (indium, uranium) and predict the existence of several (then) unknown elements (like germanium). Today we still use Mendeleev’s reasoning when predicting chemical properties of undiscovered elements (like element 114)—and it still works! We also use the Periodic Table to help us predict trends (like atomic radius, among others), which is the focus of today’s lecture. Geography of the Periodic Table A brief summary of the geography of the Periodic Table will be provided here. In general, metals lie on the left side of the Periodic Table (P.T.) and non-metals will lie to the right. The zig-zag through the periodic table is the separating lines between the two, with metalloids (elements that sometimes behave like metals, sometimes like non-metals) all along this line. There are 18 groups on the P.T. Customarily, we name these groups ‘the X-group’ or ‘the X-family’, where X represents the first element in that group. For example, group 14 would be called the Carbon group. There are other special names of which you should be aware: Group 1 is the Alkali Metals , Group 2 the Alkaline Earth Metals , Group 15 the pnictogens , Group 16 the chalcogens , Group 17 the halogens , and Group 18 the noble gases . The block in the center (Groups 3-12) is known as the transition metals or the d-block metals , while the two rows floating below the P.T. are known as the lanthanides and actinides or the f-block metals . The main group elements are defined as Groups 1 and 2 (also known as the s-block ), and Groups 13-18 (also known as the p-block ). Electron Shielding Also see the lecture entitled “The Ionic Bond”, slide 3 for a visual representation of this discussion. Electronic shielding will be employed to explain the atomic trends that we will discuss below. Think of the atom as a rock concert—there is a stage with the band
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This note was uploaded on 02/02/2009 for the course CH 53750 taught by Professor Rowland during the Spring '09 term at University of Texas at Austin.

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Lecture 6 NotesThe Periodic Table and Atomic Configurations Notes

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