1. Properties of the Periodic Table Families Chemistry Fall 2009

2. Octet Rule Atoms tend to gain, lose, or share e- in order to get a full set of 8 valence e- Useful for determining the type of ions likely to form Elements on the right side of the periodic table tend to gain e-; forming negative ions Elements on the left side of the periodic table tend to lose e- and form positive ions Why do elements on the right side gain e – and elements on the left side lose e-?

3. Family 1A Alkali metals Easily lose a valence e- and form a ion with a +1 charge Soft enough to cut with a knife Highly reactive – too reactive to be found free in nature; good conductors of heat and electricity  Example: NaCl in salt water

4. Family 1A - Lithium Lightest alkali metal Found in water, soil, and rocks Least reactive of alkali metals Compounds of lithium found in batteries and dehumidifiers Used to strengthen glass and treat bipolar disorders

5. Hydrogen Placed in 1A because it has 1 valence e- H shares many properties with nonmetals and metals Highly reactive http://www.open2.net/s ciencetechnologynature /worldaroundus/akalime tals.html http://www.open2.net/s ciencetechnologynature /worldaroundus/akalime tals.html

6. Group 2A – Alkaline Earth Metals Form compounds with oxygen called “oxides” Shiny solids that are harder than alkali metals Lose 2 valence e- to form ions with a 2+ charge

7. Calcium Found widely in nature- rocks, coral reefs Needed to maintain healthy teeth and bones Decomposition of calcium carbonate forms lime – used to manufacture steel, paper, and glass.

8. Magnesium Abundant Can be formed into any shape Alloys are strong and lightweight

9. Group 3A – The Boron Family Found in nature combined with other elements B, Al, Ga lose 3 e- to form ions with a +3 charge Thallium loses only the p valence e- to form ions with a 1+ charge

10. Boron Borax comes from California’s Mojave Desert Cleaning agent and fireproof insulation Boric acid used as disinfectant and eyewash Boron nitride – 2 nd hardest known material Super abrasives

11. Aluminum Most abundant metal in earth’s crust Recycling aluminum is energy efficient compared to extracting it from its ore Widely used – alum in antiperspirants and aluminum oxide in many gems

12. Group 4A – The Carbon Group

13. Carbon Can form many different compounds Diamonds are hard, graphite is soft – allotrope C atoms in graphite share e- with other C atoms to form layers that slide C atoms share e- with other C atoms in diamonds to form a 3-D solid

14. Silicon Computer chips and solar cells Can be found in quartz crystal, sand, and glass

15. Family 5A – The Nitrogen Group

16. Nitrogen Abundant in the atmosphere Proteins contain N Bacteria in soil convert N from the atmosphere to nitrogen compounds that are easier to use by organisms Ammonia – colorless gas, irritating odor

17. Phosphorus Phosphate compounds can be found in cheese, laxatives, baking powders, flame- retardant fabric, grease remover in cleaning products Essential for plant growth (fertilizers) – can be harmful to the environment

18. Bismuth A compound of Bismuth is an active ingredient in a remedy for nausea and diarrhea

19. Group 6A – The Oxygen Group

20. Oxygen 6 valence e-; tend to gain two e- to form ions with a 2- charge; can also share 2e- Ozone - unstable gas Most abundant element in Earth’s crust Forms compounds with every element except He, Ne, and Ar

21. Sulfur Used to make acids to be used in fertilizers, steel, paper, and paints Hydrogen sulfide used as an energy source in the ocean Hydrogen sulfide released from volcanoes Tarnish silver

22. Selenium Supplements Found in eggs, fish, and grains. Works with vitamin E to prevent cell damage Used in solar cells - converts light into electricity Locoweed – toxic levels to grazing animals copiers

23. Group 7A – The Halogens

24. Fluorine Form compounds with almost all metals Form ions with a 1- charge Added to toothpaste and drinking water to protect tooth enamel from decay Nonstick coating for cookware

25. Chlorine Highly reactive Deadly gas Compounds of chlorine are used as bleaching agents, stain removal Cl compounds are used by dentists and hydrochloric acid is used to digest food, rust removal, plastic production

26. Iodine Body needs iodine to maintain a healthy thyroid gland Seafood and iodized salt are excellent sources of iodine Kills bacteria – used by campers to disinfect water

27. Group 8A – Noble Gases

28. Helium odorless and unreactive Stable Sun Lightest noble gas Used in blimps, airships, and balloons

29. Neon Light displays High-voltage electricity passes through the neon gas stored in a gas discharge tube, e- in the atoms become excited E- return to a lower energy state and emit bright light