Topic: The Periodic Table

PSSA: 3.4.7.A/S8.C.1.1

Objective:

•TLW describe the design andstructure of the Periodic Tableand predict properties of elementsbased on their location on thetable.

MI #1: Mendeleev and the PT

•Mendeleev arranged elements inorder of increasing atomic mass.

•Atomic mass is the average massof all of the isotopes of anelement.

MI #2: Valence Patterns

•When arranged by increasing atomicmass, a pattern in the valences isfound.

•Valence is the # of electrons gained,lost, or shared during bonding.

•Valence = 1 2 3 4 3 2 1 0

•# of valence e- = 1 2 3 4 5 6 7 8

•Elements in the same column have thesame valence and similar properties.

MI #3: Moseley and the PT

•Henry Moseley determined theatomic number of each element.

•When he arranged elements byatomic #, they fell into columnswith the same valence and similarproperties without exception.

MI #4: Design of the PT (Columns)

•Each column contains a group (orfamily) of elements with the samevalence and similar properties.

MI #5: Design of the PT (Rows)

•Periods (or rows) start with anelement that is a reactive metaland end with an unreactive gas.

•Elements in the period aredifferent but their atomic massincreases as you move from leftto right.

MI #6: Design of the PT (Boxes)

•Atomic Number

•Symbol

•Name

•Atomic Mass

Carbon

12.0

So What…? Real Life Application

•Understanding the structure of thePeriodic Table of the Elementsallows us to understand therelationships between elements.