The Periodic Table

1. The Periodic Table Chapter 6 www.webelements.com

2. Why is the Periodic Table important to me? • The periodic table is the most useful tool to a chemist. • You get to use it on every test. • It organizes lots of information about all the known elements.

3. Pre-Periodic Table Chemistry … • …was a mess!!! • No organization of elements. • Imagine going to a grocery store with no organization!! • Difficult to find information. • Chemistry didn’t make sense.

4. ORGANIZING THE ELEMENTS • J. W. Dobereiner (a German) in 1829 used the chemical properties of the elements to sort them in groups of threes (triads). • Dimitri Mendeleev (a Russian) in 1869 used increasing atomic mass to order the elements. • (Remember proton was not discovered until 1886—nucleus in 1911.)

5. HOW HIS WORKED… Put elements in rows by increasing atomic mass. Put elements in columns by the way they reacted. SOME PROBLEMS… He left blank spaces for what he said were undiscovered elements. (Turned out he was right!) He broke the pattern of increasing atomic mass to keep similar reacting elements together. Dmitri Mendeleev: Father of the Table

6. The Current Periodic Table • Now the elements are put in rows by increasing ATOMIC NUMBER!! • The horizontal rows are called periods and are labeled from 1 to 7. • The vertical columns are called groups are labeled from 1 to 18 (and 1A-8A).

7. THE PERIODIC LAW When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

8. Three classes of elements are: • Metals • Good conductors of heat • Good conductors of electricity • Shiny • All are solids at room temperature except mercury (Hg) • Ductile—can be drawn into wire • Malleable—can be hammered into a sheet

9. Three Classes of elements: • Nonmetals (properties vary more than metals) • Poor conductors (except carbon) • Brittle (shatter when hit) • Most are gases at room temperature • Sulfur and phosphorus are solids • Bromine is a liquid

10. Three Classes of elements • Metalloids • They behave as metals and nonmetals depending on conditions • If boron is added to silicon, then silicon will conduct electricity = semiconductor

12. Squares in the periodic table

13. Groups = vertical columns • Elements in the same group have similar chemical and physical properties!! • (Mendeleev did that on purpose.) • Why?? • They have the same number of valence (outer energy level) electrons. • They will form the same kinds of ions (charged atoms).

14. Reactivity GROUPS • REACTIVITY INCREASES AS YOU GO DOWN A GROUP OF METALS • REACTIVITY DECREASES AS YOU GO DOWN A GROUP OF NONMETALS

15. Alkali Metals –s1 (2s1 – 7s1) • 1st column on the periodic table (Group 1 or Group 1A) not including hydrogen. • Very reactive metals, always combined with something else in nature (like in salt). • Soft enough to cut with a butter knife

16. Alkali metals

17. Cesium in water

18. Electron Configuration of Group 1A

19. Hydrogen • Hydrogen belongs to a family of its own. • Hydrogen is a diatomic—always H2, reactive gas. • Hydrogen was involved in the explosion of the Hindenberg. • Hydrogen is promising as an alternative fuel source for automobiles

20. Alkaline Earth Metals –s2 (2 s2 - 3 s2 ) • Second column on the periodic table. (Group 2 or 2A) • Reactive metals that are always combined with nonmetals in nature. • Several of these elements are important mineral nutrients (such as Mg and Ca

21. Alkaline Earth Metals

22. Transition Metals (d-block d1- d10) • Elements in groups 3-12 • Less reactive harder metals • Includes metals used in jewelry and construction. • Metals used as “uncombined” element metal. • The transition elements often act as catalysts in reactions and are often colorful in compounds.

23. Transition metals • The Group B elements

24. Boron Family p1 (2 p1 - 6 p1 ) Elements in group 13 (3A) Boron is most commonly found as borax and boric acid, which are used in cleaning compounds. Aluminum is the third most common element in the earth's crust. It is used as a coating agent, to prevent oxidation. It is an excellent conductor of electricity and heat and can be found in many cooking utensils. Gallium is important today in the production of gallium arsenide LEDs and laser diodes. Indium is a very soft metal that can actually be wiped onto other metals as an anticorrosion agent. It also has the peculiar quality of squealing when bent. Finally, thallium is quite toxic and is sometimes used in rat poisons. It has also been used in glass to make special infrared filters.

25. Boron Family

27. Carbon Family p2 (2 p2 -6 p2) • Elements in group 14 (4A) • Contains elements important to life and computers. • Carbon is the basis for an entire branch of chemistry. • Silicon and Germanium are important semiconductors.

28. More about the carbon family • The element carbon is the basis of life. It is found in all living material. Silicon is a semiconductor used commonly in computer chips and solar cells. It is also the second most abundant element in the earth's crust. Silicon dioxide, SiO2, is the major component of glass. Germanium has important semiconductor properties and is used in the computer industry. It is one of the few elements that expand when frozen. Lead has long been used for plumbing and is also used to block radiation. Tin was once used to make cans because it is relatively stable -- unreactive. Aluminum has replaced the more expensive tin today.

29. Electron configuration of Group 4A

30. Carbon Family

32. Nitrogen Family p3 (2 p3 - 6 p3) • Elements in group 15 (5A) • Nitrogen makes up over ¾ of the atmosphere. • Nitrogen and phosphorus are both important in living things. • Most of the world’s nitrogen is not available to living things. • The red stuff on the tip of matches is phosphorus. • http://www.carondelet.pvt.k12.ca.us/Family/Science/Nitrogen/thefamily.html

34. More about the nitrogen family • Nitrogen is used in saltpeter for fertilizer and explosives. It is also useful to create an oxygen-free atmosphere to prevent oxidation or combustion. A common use for liquid nitrogen today is the rapid freezing of food products. We also use liquid nitrogen in medical/surgical applications such as cryotherapy and cryosurgery. Phosphorus is used in compounds such as phosphoric acid, to make synthetic fertilizers, and in detergents. Arsenic and antimony are most commonly found in alloys used for the production of batteries and special types of solder. Bismuth is commonly used for alloys of metals and as a component of cosmetics or medicine used to treat upset stomach (Pepto-Bismol) and eczema.

35. Oxygen Family or Chalcogens p42 p4 - 6 p4) • Elements in group 16 (6A) • Oxygen is necessary for respiration. • Many things that stink, contain sulfur (rotten eggs, garlic, skunks,etc.)

36. The chalcogens (Oxygen family)

37. More about the oxygen family • Oxygen and sulfur are common elements. In fact, oxygen is the most common element (by mass) in the earth's crust. Because oxygen is second in electronegativity only to fluorine, it reacts with almost everything to form compounds here on earth. Selenium has some semimetal characteristics, such as an increase in electrical conductivity when a light is shined on it. Tellurium is a true semimetal, existing in compound with both positive and negative charges. Polonium is an extremely rare radioactive element discovered by Marie Curie and named for her native Poland. This means that the oxygen family is split between nonmetals and semimetals.

39. Halogens p5 (2 p5 - 6 p5) • Elements in group 17 (7A) • Very reactive, volatile, diatomic, nonmetals • Always found combined with other element in nature . • Used as disinfectants and to strengthen teeth.

40. The halogens

41. More about the halogens: • All of the elements of the halogen family are found in common use in everyday life. Fluorine is used in compounds to strengthen the enamel of your teeth against decay. It is also used in acid form to etch glass. Chlorine is used in our drinking water and in swimming pools to inhibit bacterial growth. It is also used in the form of chlorine dioxide to bleach wood pulp in the manufacture of very white paper. We also use chlorine in everyday laundry bleach. Chlorine compounds are used in insecticides, fireworks, and matches.

42. The representative elements (1A-7A) • Display a wide range of physical and chemical properties. • They are metals, nonmetals and metalloids. • At room temperature: most are solids, some are gases and one is a liquid. • The group number = number of electrons in outer energy level

43. 8A0 1A 2A 3A 4A 5A 6A 7A • The elements in the 1A-7a groups are called the representative elements

44. The Noble Gases • The noble gases are used in industry in arc welding, to dilute the oxygen in deep-sea divers' gas tanks, and to fill light bulbs. Argon is used in arc welding and in common light bulbs, as it does not react with the metal at high temperatures. Helium is used for diluting the pure oxygen in deep-sea diving tanks because the helium has a low solubility in human blood. Helium is also used to inflate the tires of large aircraft, weather balloons, and blimps because it is nonflammable. Neon is used in sign tubing because it glows bright red when electricity is passed through it. Krypton and xenon are used in photographic flash units and in lighthouses, as running an electric current through either element generates a very bright light.

45. The Noble Gases p6 (2 p6-6 p6) except for He =1s2 • Elements in group 18 (8A) • VERY unreactive, monatomic gases • Used in lighted “neon” signs • Used in blimps to fix the Hindenberg problem. • Have a full valence shell.

46. The Noble Gases

47. More Noble Gases • Since all noble gases are colorless, odorless gases at room temperature, here are some pictures of how you might find them in use. • Xenon in headlights • Radon leaking into homes.

48. Electron Configurations in Groups • Noble gases:

49. Transition metals the “d” block inner transition metals the “f” block • Group 3-12 (B)