Chapter 3The Periodic Table

Development of the Modern Periodic TableJ.W. Döbereiner•Classified some elements into groups of three,

which he called triads •Elements in a triad had similar chemical

properties, and their physical properties varied in an orderly way according to their atomic masses

Development of the Modern Periodic TableJohn Newlands•Arranged elements by increasing atomic mass•Their properties repeated every 8th element•Known as the law of octaves

Development of the Modern Periodic TableDmitri Mendeleev•Demonstrated a connection between atomic

mass and elemental properties•Arranged elements in order of increasing atomic

mass•Predicted the existence and properties of

undiscovered elements•Based his table on 60 or so elements

Development of the Modern Periodic TableHenry Moseley•Discovered that atoms contain a unique number

of protons called the atomic number•Arranged elements in order of increasing atomic

number, which resulted in a periodic pattern of properties

The Modern Periodic Table•Arranged in order of increasing atomic number which increases as you move across rows called periods•Elements with similar chemical properties appear in the same column called groups•Properties change in an orderly progression across the rows from left to right

Periodic law•The physical and chemical

properties of the elements repeat in a regular pattern when they are arranged in order of increasing atomic number

Types of ElementsMetals Nonmetals Generally shiny when

smooth and clean Solid at room temperature Good conductors of heat

and electricity Malleable and ductile Loosely held valence

electrons Have high melting points

Generally gases at room temperature

Brittle, dull-looking solids Poor conductors of heat

and electricity Tightly held valence

electrons Lower melting points than

metals

Types of ElementsMetalloids•Have physical and chemical properties

of both metals and nonmetals•Also called semimetals and

semiconductors•Lie along the border between metals

and nonmetals

Groups of Elements

Group 1 Alkali metalsGroup 2 Alkaline earth metals1st Row Lanthanide Series (Lanthanoid)2nd Row Actinide Series (Actinoid)Group 16 Chalcogens (Oxygen Group)Group 17 HalogensGroup 18 Noble gasesGroups 3-12 Transition Elements (Metals)