The Periodic Table—Categories (Chapter 6)

Dmitri Mendeleev 1869 Arranged known (63) elements by increasing atomic mass Also grouped by similarities (physical properties, what they react with, etc)

Henry Moseley My hero Father of Modern Periodic Table (50 yrs after Mendeleev’s Table) Arranged elements by atomic number (after discovery of protons/neutrons/electrons) and chemical properties Studied under Rutherford

Parts of the Periodic Table: Period – describes a horizontal row on the Periodic Table Group / Family – describes a vertical column on the Periodic Table

What do these parts tell us? Periods represent the number of energy levels in the atom Groups represent the typical number of valence electrons in the outer most energy level (representative elements only!) Groups are arranged according to similar chemical properties

Where are the… Metals found? (To the left of the metalloid line, exception: H) Nonmetals found? (To the right of the metalloid line) Metalloids found? (Touching the metalloid line. Exception: Aluminum)

What are metals, nonmetals, metalloids? Metals: Elements that tend to lose electrons when forming ions, usually solid at room temp Nonmetals: Elements that tend to gain electrons when forming ions, usually gas at room temp Metalloids: Elements that either gain or lose electrons when forming ions, solid at room temp

Representative Elements Transition Elements Groups 1,2,13-18 Consist of elements that show a wide range of chemical and physical properties Referred to as group “A” Could have unfilled s or p sublevels in their highest energy level Groups 3-12 Consist of elements that connect representative elements Referred to as Group “B” Could have unfilled d or f sublevels in their highest energy level

Let’s identify the following groups: Alkali Metals Alkaline Earth Metals Transition Metals Boron Group Carbon Group Nitrogen Group Oxygen Group Halogens Noble Gases Lanthanide Series Actinide Series