Organization of the Periodic Table

History Dmitri Mendeleev (1860s) was the first to organize the elements by atomic mass Even predicted elements to be discovered Grouped by families and similar properties Not correct Someone else organized it by atomic number 1914 Henry Mosely, determined number of protons in an atom

How are elements arranged? Arranged according to their atomic number from left to right Each element block contains the same type of info (atomic #, symbol, atomic mass) Periods are the rows in the periodic table Group OR Family is the vertical column Arranged together because of their similar properties

Definition of Property A property is a characteristic You will see this word for the following units, get use to it! EXAMPLES: Physical chemical

The Lanthanide and Actinide Series Pg294 Rare Earth elements Placed at the bottom of the table to save space

REGIONS OF THE PT Metals Nonmetals Metalloids Light blue area Located to the left of the zig zag line Nonmetals Yellow area Located to the right of the zig zag line Metalloids Light green area Located at the zig zag line

Metals Located to the left of the zig zag line Majority of elements are metals Properties: Luster Metallic Malleable Ductile Conductivity (heat and electricity)

Nonmetals Located to the right of the zig zag line. Nonmetals are found in lasers, plastics, air your breathe Carbon (nonmetal) is important to all living things Properties: Poor (not good) conductors of heat and electricity Do not have luster Cannot be easily shaped

Metalloids Located at the zig zag line AKA Semimetals Have properties of both metals and nonmetals Semiconductors – can conduct electricity Silicon is an important semiconductor found in your computers and phones