2.2.2 The Periodic Table

1. 2.2.2 The Periodic Table See page 104 Origin Of The Periodic Table • Chemists in the 19th century wished to organize elements • Attempts focused on grouping elements with similar properties • In 1867, Dimitri Mendeleev found patterns in the elements and organized them into a table • The resulting table had holes for elements not yet discovered

3. Some of Dalton's symbols for the elements with his estimates of molecular weight

4. Extended Dalton Table

5. Hinrichs’s Spiral Periodic System G.D. Hinrichs’s spiral periodic system of 1867. Programm der Atomechanik oder die Chemie eine Mechanik de Pantome, Augustus Hageboek, Iowa City, IA, 1867.

6. Meyer's Spiral System of 1872 (from van Spronsen):

7. Meyer's "Lost" Table of 1868 In his book, The Periodic Table: A Very Short Introduction, Eric Scerri writes how Lothar Meyer produced an expanded periodic system for his1868 textbook which contained 53 elements. Unfortunately, the table was misplaced by the publisher and was not appear until after his death in 1895.

8. 1886 Crookes' Periodic Table

9. Periodic Table See page 107 The Periodic Table provides information on the physical and chemical properties of elements Atomic Mass - mass of average atom Atomic Number - number of protons Ion Charge - electric charge that forms when an atom gains or loses electrons

10. Periodic Table See page 106

12. Periods and Families See pages 107 • Alkali metals - highly reactive group 1 • Alkaline earth metals - group 2, burn in air if heated • Halogens - group 17, highly reactive non-metals • Noble gases - group 18, stable and unreactive non-metals • Each horizontal row in the periodic table is a period • Vertical columns form groups or chemical families Check out this table: http://elements.wlonk.com/ElementsTable.htm

13. Metals, Non-metals, Metalloids See page 110 • Period table has patterns • Due to Mendeleev’s organization, patterns are created, such as the groups: metals, non-metals and metalloids.