REPRESENTATIVE GROUPS

Valence Electrons

• A valence electron is an electron that is in the highest occupied energy level of an atom
• electrons play a key role in chemical reactions
• properties vary across a period because the number of valence electrons increase from left to right.
• elements in a group have similar properties because they have the same number of valence electrons

Alkali Metals

• metals with 1 valence electron & are extremely reactive
• found in nature only in compounds ( most familiar is table salt)
• Not all elements in a group are extremely reactive
• Sodium is as hard as cold butter and can be cut with a knife
• It also melts at about 98 degrees celsius and has a lower density than water

Alkaline Earth Metals

• 2 valence electrons
• Differences in reactivity is shown by the ways they react with water
• Melting Point of Magnesium is 650 degrees celsius
• Magnesium & Calcium have essential biological functions your body needs calcium to keep your bones & teeth strong
• Magnesium plays a key role in the process called photosynthesis

Boron Family

• 3 Valence electrons
• Contains Aluminum the most abundant metal in Earth's Crust
• 10% or more is used in packaging

Carbon Family

• 4 valence electrons
• life wouldn't exist without carbon
• Except water most compounds in your body contain carbon

Nitrogen Family

• 5 Valence electrons
• Nitrogen & Phosphorus are the most common elements in fertilizers
• We also use compounds containing Nitrogen & Phosphorus to release energy in food

Oxygen Family

• Also known as Chalcogens 6 Valence Electrons
• Oxygen is the most abundant element in Earth's crust Ozone is another form of oxygen in the ozone layer
• Complex life forms need oxygen to live because it is used to release energy in food
• Sulfur was one of the first elements to be discovered because it's found in large natural deposits

Halogens

• 7 valence electrons
• highly reactive non-metals that react easily with most metals
• Chlorine is used to kill bacteria in drinking water and swimming pools
• A flourine compound is used to prevent tooth decay
• Iodine is used by our body to keep our Thyroid Gland working properly which controls reactions in the body

Noble Gases

• 8 valence electrons
• colorless, odorless,and not easily reactive thus not easy to discover
• All Noble Gases are used in "Neon Lights" except radon
• Some light bulbs are filled with Argon
• This filament will not react with argon as it would with oxygen