Topic: The Periodic Table PSSA: A/S8.C.1.1
Objective: TLW describe the design and structure of the Periodic Table and predict properties of elements based on their location on the table.
MI #1: Mendeleev and the PT Mendeleev arranged elements in order of increasing atomic mass. Atomic mass is the average mass of all of the isotopes of an element.
MI #2: Valence Patterns When arranged by increasing atomic mass, a pattern in the valences is found. Valence is the # of electrons gained, lost, or shared during bonding. Valence = # of valence e - = Elements in the same column have the same valence and similar properties.
MI #3: Moseley and the PT Henry Moseley determined the atomic number of each element. When he arranged elements by atomic #, they fell into columns with the same valence and similar properties without exception.
MI #4: Design of the PT (Columns) Each column contains a group (or family) of elements with the same valence and similar properties.
MI #5: Design of the PT (Rows) Periods (or rows) start with an element that is a reactive metal and end with an unreactive gas. Elements in the period are different but their atomic mass increases as you move from left to right.
MI #6: Design of the PT (Boxes) Atomic Number Symbol Name Atomic Mass 6 C Carbon 12.0
So What…? Real Life Application Understanding the structure of the Periodic Table of the Elements allows us to understand the relationships between elements.