Starter: What is the proton, electron, and neutron for Sulfur?

Organizing the Elements Chapter 4, Section 2 Organizing the Elements

Periodic Table Group by group, Mendeleev arranged the 63 known elements based on their properties: Melting point If they tarnish If they react with water Etc. Periodic means “in a regular, repeated pattern” Table Talk: Discuss why Mendeleev put question marks in his original periodic table. (Hint, there were only 63 known elements at the time) See Discovery Education video“Periodic Table” (3:55) – from “Greatest Discoveries with Bill Nye – Chemistry”

Modern Periodic Table More than 100 elements Arranged in order of increasing atomic number (# of protons) The properties of an element can be predicted from its location on the periodic table See Active Art: http://www.phschool.com enter code cgp-1032

http://periodictable.com/ Click here to see an interactive, illustrated version of the Periodic Table

More About the Periodic Table Classes of Elements Atomic numbers increase from left to right Table is color-coded to classify types of elements Metals Non-metals Inert gases

Periods Horizontal rows Metals on left, with most reactive metals on far left Non-metals on the right with most reactive next to the inert gases on the far right Semi-metals between the metals and non-metals

Groups Vertical columns Also known as a “family” Consists of elements with similar characteristics Lanthanides and actinides do not belong in the 18 groups and have been pulled out

Table Talk: Discuss the difference between groups and periods on the periodic Table

Reading the Data Calcium In our textbook, each square on the Periodic Table lists 4 pieces of information: An element’s atomic number Chemical symbol Name Atomic mass Calcium Table Talk: Discuss what information the atomic number and atomic mass give us. See BrainPop “Periodic Table” end

Starter: March 17th What is the Atomic number Mass Number Proton Electron Neutron