The Groups of the Periodic table of elements What is the relationship between the group number and chemical properties of the elements?

Most reactive metals in the periodic table Group 1 – Alkali Metals Most reactive metals in the periodic table Shiny, and soft like butter but still solids Low densities and melting points

Group 2 – Alkaline Earth Metals Not quite as reactive as group 1 Two valence electrons Harder and denser than Alkali metals React with water

Groups 3-12 – Transition metals Most of These metals are hard, shiny solids Mercury is a liquid Less reactive than groups 1 and 2

Carbon is important in the chemistry of life Group 14 – Carbon Family Carbon is important in the chemistry of life Organic compounds contain carbon Most fuels contain carbon

Group 15 – Nitrogen Family Nitrogen makes up 78% of the atmosphere Nitrogen is a diatomic molecule Nitrogen fixation from atmosphere is crucial for plants to grow

Oxygen is also diatomic Group 16 – Oxygen Family Oxygen is also diatomic Oxygen is reactive and can combine with almost every other element Sulfur is a brittle yellow solid

Halogen means “salt forming” Most reactive non-metals Group 17 – The halogens Halogen means “salt forming” Most reactive non-metals When a halogen bonds with an alkali metal it is called a “salt”

Do not form compounds because they do not normally react Group 18 – Noble Gasses Do not form compounds because they do not normally react Also called inert gasses Have 8 valence electrons

Chemical properties are very different from all other elements hydrogen Chemical properties are very different from all other elements Makes up over 90% of all of the atoms in the universe Hydrogen fusion defines a star