1. I II III Periodic Table of the Elements

2.  1700’s – about 30 elements identified  Antoine Lavoisier Early Development of P.T. Antoine Lavoisier's Traité Élémentaire de Chimie, 1789, as quoted in J. R. Partington's A Short History of Chemistry (Dover, 1989, ISBN 0486659771).

3.  J.W. Dobereiner  Triads (groups of 3)  Similar Properties  Mass of middle element was close to the average of the other two in the triad. Early 1800’s

4.  J.A.R. Newlands  62 elements arranged by atomic mass  Similar Properties with every 8 th element  Law of Octaves 1865

5.  Dmitri Mendeleev – 1 st periodic table.  Arranged by atomic mass & how one element reacted with other elements.  Left gaps for undiscovered elements. 1869

6. Mendeleev’s Periodic Table

7.  Determined the nuclear charge of the atom.  Modified Mendeleev’s P.T.  Arranged elements by increasing atomic number. Henry Moseley 1913

8.  Elements are arranged in order of increasing atomic number so that elements with similar properties fall in the same column. Modern Periodic Table

9.  The physical and chemical properties of the elements are periodic functions of their atomic numbers.  When elements are arranged in order of increasing atomic number, elements with similar properties appear at regular intervals. Periodic Law

10.  Metals  Nonmetals  Metalloids Organizing the Squares  Groups – Vertical  Groups have similar chemical and physical properties.  Periods – Horizontal Rows

11.  Representative Elements  Transition Metals  Inner Transition Metals – Lanthanide & Actinide Series Group Labels

12. Group Names  Alkali Metals  Alkaline Earth Metals  Halogens  Noble Gases

13. “Blocks” s-block f-block d-block p-block

14.  Valence electrons – responsible for properties of elements.  Same groups = similar electron configurations = similar properties Electron Configuration

15.  Group # tells you how many valence electrons there are. Representative elements  Outermost s & p sublevels are only partially filled. 1A 2A 3A 4A 5A 6A 7A 8A

16.  Chemically Reactive Metals  Group 1 – Alkali Metals (most reactive) Soft, silvery, can be cut with a knife.  Group 2 – Alkali Earth Metals (harder, denser, stronger than alkali metals).  Too reactive to be found in nature as free elements. s-Block

17.  Main group elements  All nonmetals (except H)  All metalloids  Halogens – most reactive nonmetals.  Noble Gases - inert p-block

18. Transition Metals  Outermost s sublevel and nearby d sublevel contain electrons. Transition Metals

19.  Metals with typical “metal” properties … gold, silver, etc.  Transition elements  Fairly unreactive  Some exist in nature as free elements d-block

20.  Outermost s & p sublevels are filled.  Inert Gases (do not readily react). Noble Gases

21.  Hydrogen is unique – does not fit in with any group.  Helium fits in best with group 18 because its highest energy level is full and it is nonreactive or inert. Hydrogen and Helium

22. *Inner Transition Metals  Outermost s sublevel and nearby f sublevel contain electrons. Inner Transition Metals

23.  Lanthanides and Actinides  Lanthanides – shiny metals similar in reactivity to alkaline earth metals.  Actinides – all are radioactive f-block