THE PERIODIC TABLE
        Objective:  Explain the use of chemical and 
        physical properties in the historical 
        development of the Periodic Table.
        ■ Antoine Lavoisier:   In the 1700’s complied a list of all know elements (33) organized 
          into 4 categories.
           – Gases (light, heat, inflammable air, etc.)
           – Metals (antimony, silver, arsenic, bismuth, zinc, etc.)
           – Nonmetals (sulfur, phosphorus, pure charcoal, etc.)
           – Earths (chalk, clay, siliceous earth, etc.)
        ■ John Newlands:  In 1864 he noticed that when the elements were arrange in order 
          of increasing ATOMIC MASS that the properties REPEATED EVERY 8 ELEMENTS.  
           – This pattern is called PERIODIC.
           – Called this the Law of Octaves.
           – Not accepted because did not work for all elements and “octave” sounded 
             “unscientific.”
       Dmitri Mendeleev:  1869
       Father of The Periodic Table
                           ■ Also noticed that when the elements were arranged 
                             by atomic mass that there was a Periodic Pattern in 
                             their properties.
                           ■ His table had vertical rows and horizontal columns.
                           ■ The Columns had SIMILAR PROPERTIES.
                           ■ Left BLANK SPACES for undiscovered elements.
                           ■ Predicted the properties for:
                             – scandium
                             – gallium
                             – germanium
                           ■ LotharMeyers demonstrated the same connection 
                             but Mendeleev was FIRST.
            Henry Moseley (1887 – 1915)
                                                               ■ MODERN PERIODIC TABLE
        ■ Problems with Mendeleev’s table:
            – As new elements were discovered did not fit      ■ Vertical Columns:
                                                                   –  Groups or Families
               pattern.                                            –  18 groups
        ■ Henry Moseley discovered that each element had a  ■ Horizontal Rows:
           UNIQUE NUMBER OF PROTONS.                               –  Periods
                                                                   –  7 periods
        ■ This is the ATOMIC NUMBER.                           ■ Representative Elements:
                                                                   –  groups 1, 2, 13-18
        ■ In 1913 he proposed that the Period Table be         ■ Transition Elements:
           organized by Atomic Number which gave a CLEAR           –  groups 3-12
           Period Pattern.                                         –  Inner Transition Metals
        ■ PERIODIC LAW:  There is a periodic repetition of     ■ Also classified as:
                                                                   –  metals
           chemical and physical properties of the elements        –  nonmetals
           when they arranged by increasing ATOMIC NUMBER.         –  metalloids