2.2.2 The Periodic Table Origin Of 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
A period is a section of something e.g., in hockey the game is split into 3 periods The section of words that make up this sentence ends in a period. A type of unit of time in geology is called a period.
Side note: Here are some representations in a more realistic scale.
Some of Dalton's symbols for the elements with his estimates of molecular weight
Extended Dalton Table
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.
Meyer's Spiral System of 1872 (from van Spronsen):
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.
1886 Crookes' Periodic Table
Periodic Table The Periodic Table provides information 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
Periodic Table See page 106
Periods and Families See pages 107 Each horizontal row in the periodic table is a period Vertical columns form groups or chemical families 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 Check out this table: http://elements.wlonk.com/ElementsTable.htm
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.