Modern Periodic Table

Modern Periodic Table Arranged by increasing Atomic Number Rows Called Periods 7 Periods Higher Number = more available electron energy levels

Horizontal Rows Called Periods 1-7 2 3 4 5 6 7

Groups Vertical Columns Called Groups or “families”. Elements in same Group have similar chemical properties All have same # of valence electrons

18 Groups (Vertical Columns)

Periodic Law Pattern of repeating properties of elements in groups

Cl 17 Chlorine 35.453 4 pieces of information in any square Atomic Number Element symbol Element Name Average atomic Mass in amu 4 pieces of information in any square

Classes of Elements Atomic Numbers 1-92 occur naturally Atomic numbers 93 and higher do not occur naturally Synthetic (man made)

3 General Classes of Elements 1. Metals: Good conductors of heat & electricity Majority of Elements On left side bold staircase Most are malleable (hammered w/out shattering) & ductile (drawn into wires) Most are solid except mercury (liquid)

3 General Classes of Elements 2. Nonmetals: poor conductors of heat & electricity Properties opposite of metals To the right of bold staircase Many are gases; solid ones are brittle (break when hit)

3. Metalloids: Properties fall in between metals & nonmetals Found on bold staircase Ability to conduct electricity varies with temperature Only conduct electricity at high temps. Called semiconductors; used in computer chips Ex: Silicon

Nonmetals Metals Metalloids

Periodic Trends From left to right across a period: Elements become less metallic & more nonmetallic