The organization of elements is the periodic table.
Each square contains the name of an element and the letter symbol for that element (some symbols were derived from the Latin name for the element).

The vertical columns of the periodic table are called groups , or families .
• Each group contains elements with similar chemical properties .

The horizontal rows of elements in the periodic table are called periods .
• Physical and chemical properties change somewhat regularly across a period.

There are two main sections of the periodic table
-metals and nonmetals .
Metals are elements that are good conductors of heat and electricity.
• Gold, copper, and aluminum are metals.

Properties of Metals
• most are solids at room temperature
• malleable – they can be hammered or rolled into thin sheets
• ductile – they can be drawn into a fine wire .

Alkali metals (group 1) do not occur in nature as elements.
They have a silvery luster , a low melting point , and are reactive .
They react with oxygen and water so must be stored in oil (kerosene).

Alkaline Earth metals (group 2) do not occur naturally in their elemental state.
They occur as carbonates , phosphates , silicates , and sulfates . These metals also have a silvery luster .

Transition metals have a silvery luster, except for gold and copper .
These metals are harder and more brittle than metals in groups 1 and 2.
Scandium Titanium Chromium

Nonmetals are poor conductors of heat and electricity.
Properties of nonmetals
• many are gases
• solids are brittle

Halogens (group 17) are all nonmetals . These elements are found in the rock of Earth’s crust and dissolved in seawater.
Chlorine
Bromine
Iodine

Noble gases are found in group 18 and are unreactive .
The light weight of helium makes it useful in blimps.
Neon and argon are used in
“neon lights” in advertising.

Metalloids (semiconductors) have characteristics of both metals and nonmetals.
Some metalloids can conduct electricity better than most nonmetals , but not as well as some metals, giving them the name semiconductor .
With the exception of aluminum, the metalloids are the elements in the periodic table that are located along the stairstep line.