CH 05 - notes

PHYSICAL SCIENCE ~ THE PERIODIC TABLE OF ELEMENTS

CH 05 - notes

Periodic table of elements John NewlandsJ.W. Dobereinergrouped elements in arranged elements in “triads” according to groups of “eights” according to their their similar properties properties.

1829

1864

Lothar Meyerarranged elements according to atomic weight

1870

Periodic table of elements 

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Dmitri Mendeleev- Russian scientist published the 1st table of elements in 1869 ( ~ 63 elements) He arranged the elements according to increasing atomic weight AND their properties- Left gaps for undiscovered elements. Known as the “Father of the Periodic Table of Elements” Henry Mosley(1913) – arranged the table according to the atomic number. Today it is arranged according to increasing atomic number

Periodic Law- The chemical and physical properties of the elements will repeat themselves in a predictable way when the elements are arranged according to increasing atomic number http://ed.ted.com/lessons/the-genius-of-mendeleev-speriodic-table-lou-serico

Periodic Table of Elements 

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Vertical columns: groups or families Horizontal rows: periods Elements in the same group have similar chemical and physical properties  Because the elements in a group have the same number of valence electrons Properties dissimilar left to right across a period Elements in a period – their valence electrons found on the same energy level