1. Introduction to the Periodic Table Chapter 15-1

2. Today’s Periodic Table Elements organized by increasing atomic number Rows (periods) labeled 1-7 Period—row of elements whose properties change gradually and predictably 18 columns (group or family) Group—elements that have similar physical or chemical properties

3. Periodic Table Divided into two sections 1 st Section: Groups 1-2 and Groups 13- 18 Representative elements Include metals, nonmetals, metalloids 2 nd Section: Groups 3-12 Transition elements All metals

5. Metals All metals are solid, with the exception of mercury Most have high melting points Have luster (reflect light) Good conductor of heat and electricity Malleable (can be pressed or pounded into thin sheets or shaped into objects) Ductile (can be drawn out into wires)

6. Nonmetals & Metalloids Nonmetals Gases or brittle solids Poor conductors of heat and electricity 17 nonmetals Many essential for life C, S, N, O, I Metalloids Shares some properties with metals and some with nonmetals Also called semimetals

7. Element Keys Box on periodic table to represent element

8. Symbols for Elements One or two letter abbreviations Often based on element name Symbol might also come from Greek or Latin names (Iron=Fe, latin for iron is ferrous) Some elements named for scientists Others named for geographic locations

9. Symbols for Elements New elements are given a temporary name and 3 letter symbol Once discovery is verified, discoverers can choose permanent name