Modeling Atoms: Elements and the Periodic Table

1. Chemical Building BlocksChapter 3 – Elements and the Periodic Table Section 2 -

2. Modeling Atoms • Atoms are too small to see, so scientists need models! • Model = diagram, mental picture, math statement, or object that helps explain ideas about the natural world.

3. DO NOW • How are the letters of the alphabet similar to the elements?

4. COMBINATIONS OF 26 LETTERS make up every word in the English language. • Similarly, all material things in the world are composed of different combinations of about 100 different elements. • An element is a substance that cannot be broken down into simpler substances through ordinary chemistry--it is not destroyed by acids, for example, nor changed by electricity, light, or heat.

5. http://www.nclark.net/PeriodicTable

6. Dmitri Mendeleev ** Atomic mass = the average mass of all the isotopes of that element.

7. Modern Periodic Table • Element properties repeat “periodically” • Arranged according to atomic number (# of protons) [Thanks to Henry Moseley in 1913]

8. EACH ELEMENT: • Has it’s own square, and: • 1. atomic number • (# of protons) • 2. chemical symbols and names • First letter capitalized, followed by 1 or 2 more letters • Some symbols are based off of Latin names • Ex: Pb = lead = plumbum, Au = gold = aurum, Na = sodium = natrium • 3. average atomic mass

9. Organization of Periodic Table • COLUMNS • Aka Families • Members have similar characteristics • Normally named after first element in each group (ex: carbon family and nitrogen family) • EX: • Group 1 react violently w/ water • Group 2 reacts slowly or not at all w/ water • Group 18  rarely react • ROWS • properties change as you move left to right • Less reactive as you move right • 7 of them • All of the elements in a period have the same number of atomic orbitals

11. DO NOW • Look at the aluminum foil, the aluminum container, and the aluminum can. • List as many properties of aluminum as you can think of. • Compare the shapes, thickness, and general appearance of the objects. • What would happen if you tried to bend and unbend each object.

12. METALS • Physical Properties = • 1. shininess

13. 2. malleability • Able to be hammered or rolled thin into flat sheets and other shapes

14. 3. ductility • Able to be pulled out into a long wire

15. 4. conductivity • Ability to transfer heat or electricity to another object

16. 5. All but Mercury are solids at room temp

17. Iron in Cereal • http://www.youtube.com/watch?v=V265pGgsBnM

18. METALS, continued • Chemical Properties • 1. Reactivity • The ease & speed w/ which an element combines, or reacts, w/ other elements • Some are EXTREMELY reactive • Others HARDLY react • http://www.youtube.com/watch?v=92Mfric7JUc&feature=related • Corrosion = the gradual wearing away of a metal element because of a chemical reaction

19. Corrosion

20. With your partner • Be able to label on periodic table where your metals are located. • Give examples of properties of your metals • Give common uses of your metals.

21. ALKALI METALS • http://www.youtube.com/watch?v=m55kgyApYrY • http://www.youtube.com/watch?v=PyFLvSg6ZDw

22. Alkali Metals • Group 1 • React by losing 1 electron • Super reactive – always combined with other elements in nature • Shiny and soft

23. Alkali Metals, cont’d

24. Facts about Alkaline Earth Metals • Group 2 • Good conductors • React by losing 2 electrons • Fairly hard, gray-white • A little less reactive than alkali

25. Alkaline Earth Metals

26. Facts about Transition Metals • Groups 3 – 12 • Mostly familiar metals • (iron, copper, nickel) • Mostly hard and shiny • Many form colorful compounds • Not as reactive as 1st 2 groups!!

27. Transition Metals

28. Metals in Mixed groups • Aluminum • Gallium • Indium • Thallium • Tin • Lead • Bismuth

29. Metals in Mixed Groups

30. DO NOW • Look at Page 84. • What are the bottom two rows of elements called? • Why are they below all of the others ? • What is significant about elements 93 – 102?

31. RARE EARTH ELEMENTS What groups did we talk about so far?? http://periodictable.com/

32. LANTHANIDES Why do you think they are called “lanthanides” ?? - Hint: Look at your periodic table on page 84!!! Are lanthanides Metals or Nonmetals?

33. Lanthanides • Soft metals…. (what do we know about them if they are metals???) • Mixed with more common metals to make alloys • Alloy = a mixture of a metal with at least one other element, usually another metal • Normally found combined with each other!

34. Alloys

35. Alloys - Continued

36. Lanthanides

37. Where do we see LANTHANIDES in everyday life???

38. - Lanthanum = Used in flints for lighters and in electron microscopes. Praseodymium = used by glassblowers Cerium = used in lighter flints, catches fire easily when struck, used for sparking special effects Neodymium = used in alloys to make very powerful permanent magnets …used in headphones, disk drives, motors

39. Actinides

40. Actinium - Can be used to generate intense heat! The rock probably contains just a few atoms of protactinium at any one time….but it’s the best we can do! It is hard to acquire • The Actinides are mostly radioactive. • Uranium is used in nuclear power plants to produce energy. • Nuclear reactors used to power submarines too! http://www.youtube.com/watch?v=fjgdgAhOzXQ

41. Actinides A radioactive button like this is inside most smoke detectors. A trace of americium creates charged particles that betray the smoke. Americium is thus the only man-made element available in grocery stores.

42. Actinides in Real Life • Two major types of atomic bombs by US during World War II. 1. A uranium-based device ( “Little Boy”) 1. A plutonium-based device ( “Fat Man”). • The uranium-based Little Boy device became the first nuclear weapon used in war when it was detonated over the Japanese city of Hiroshima on 6 August 1945. • Exploding with a yield equivalent to 12,500 tons of TNT, the blast and thermal wave of the bomb destroyed nearly 50,000 buildings and killed approximately 75,000 people. • Initially it was believed that uranium was relatively rare, but within a decade large deposits of it were discovered in many places around the world. • http://www.youtube.com/watch?v=fWoNDxjOksM&feature=related • http://www.youtube.com/watch?v=Xs3JE4WRL-8&feature=related

43. Synthetic Elements Elements higher than 92 were man-made when nuclear particles were forced to crash into one another. Very Unstable. • Particle accelerator = move atomic nuclei at very high speeds • Curium = first synthetic element

44. Particle Accelerators • Particle accelerators  they move atomic nuclei faster and faster until they have reach very high speeds. If different elements collide fast enough, they might combine! • First synthesized element was Curium – made in Chicago! Curium provides power for some equipment on the Mars Rover

45. SOOO….. • What are the 2 bottom rows of the periodic table called? • 1. • Like to form alloys!!!! ^ • 2. • Radioactive and unstable • How do scientists make elements that are heavier than uranium?

47. NONMETALS • Most are: • poor conductors • reactive with other elements. • Solid nonmetals are dull and brittle , not malleable, not ductile • 10 are gases, a few are solid, 1 is liquid

48. Nonmetals – Chemical Properties • Most are reactive and readily form compounds • Fl = most reactive element! • They gain/share electrons when reacting w/ other atoms • Metals GIVE electrons, nonmetals GAIN electrons • SALTS =metal + nonmetal • Nonmetals together share electrons

49. Families of Nonmetals • 1. Carbon Family • 2. Nitrogen Family • 3. Oxygen Family • 4. Halogen Family • 5. Noble Gases • 6. Hydrogen

50. CARBON FAMILY Carbon is in all living things!!!! There are many forms carbon can be found in. (coal, gasoline, diamonds) C Si Ge Sn Pb