Chapter 19: Elements And Their Properties

1. Chapter 19: Elements And Their Properties

2. Goals For Section 1 • Describe the properties of a typical metal. • Identify the alkali metals and alkaline earth metals. • Differentiate among three groups of transitions

3. A. Properties of Metals • Conduct heat and electricity. • Luster- reflect light well. • Malleable- can be hammered into sheets. • Ductile- can be drawn into wires. • Ionic bonding- combine with nonmetals by losing electrons. • Metallic bonding- ions are in sliding layers and electrons are weakly held.

4. B. The Alkali Metals • These are softer and more reactive than other metals. • Highly reactive with oxygen and water; don’t occur naturally as elemental forms. • Combine readily with other elements due to single electron in outer layer

5. 3. Multiple uses • Human health- sodium, potassium, and lithium compounds. • Photocells- some depend of rubidium or cesium • Francium- a radioactive element that breaks down giving off particles and energy

6. Science Warm-up 9/19/2013 • I want you to describe what makes you different from the person next to you. Do you have different appearances? Do you have different personalities? What causes these differences? • Your response to these questions should be a minimum of 5 sentences and will be left inside of your folders. I appreciate you working quietly and individually.

7. C. Alkaline Earth Metals • Not found naturally in elemental form • Two electrons in outer shell (group 2)

8. Applications: • Strontium and magnesium found in fireworks • Magnesium in ladders, vehicles and bats. • Calcium in statues and countertops

9. Human Body • Calcium in bones • Barium in disease diagnosis • Radium formerly used in cancer treatment

10. Poster Requirements • Atomic # Each # worth 2 points Poster • Electron Dot Diagram in total 20 points • Atomic Drawing • Atomic mass • Group name (alkali, transition metal etc.) • Symbol • Slogan to remember the name • # of each atomic particle (pro, neu, e) • Coherent Design • Use of Colors

11. Science warm-up 9/20/13 • As a burglar reaches for something on the mantle, he accidentally knocks over a clock. It falls to the floor, breaks, and stops. The next morning, however, police aren’t able to determine what time the robbery took place. Why not? • Two burglars enter a wealthy neighborhood late one night and take everything they can get their hands on. A police officer is upset with what he sees but doesn’t do anything about it. Why not?

12. D. Transition Metals • They often occur in nature as uncombined elements. • Typically form colored compounds– chromium is found in rubies and emeralds

13. Iron triad– iron, cobalt, and nickel • Iron- most widely used of all metals and main ingredient in steel. • Cobalt- used in some steels • Nickel- used to coat other materials

14. 3. Copper, Silver and Gold • Coinage metals that are commonly used in coins • Copper- used in electrical wiring because of superior electrical conduction. • Silver- used in photographic film and paper; jewelry • Gold- used in jewelry

15. 4. Zinc , Cadmium And Mercury • Group 12 on the periodic table • Zinc and Cadmium- often used to coat or plate other metals. • Mercury- only room temperature liquid metal; Used in thermometers and batteries

16. E. Inner Transition Metals • Seem disconnected from the rest of the periodic table. • Lanthanides- include lanthanum, cerium, praseodymium, amarium, europium, gadolinium, and terbium • Actinides- all are radioactive and unstable; uranium is the best known.

17. Science Warm-up 9/23/2013 • There are three houses, and three utilities: gas, electricity and water. Your task is to connect each house to all three utilities. Therefore each house will have three lines and each utility will also have three lines. However, you cannot cross lines. You cannot pass lines through houses or utilities. You cannot share lines. Can you draw the 9 lines required?

19. Section 2: Nonmetals • Goals: • Recognize hydrogen as a nonmetal. • Compare and contrast properties of the halogens. • Describe properties and uses of noble gases.

20. Properties of Nonmetals • Nonmetals are usually • Gases or brittle solids at room temperature. • Are not malleable or ductile • Usually poor conductors of heat and electricity • Usually not lustrous

21. Ionic Compounds • These form when nonmetals gain electrons from metals and become negative ions.

22. 2. Covalent Compounds • These form when nonmetals share electrons with other non metals.

23. B. Hydrogen • Hydrogen is the most common element in the universe. • A diatomic molecule- two atoms of the same element in a covalent bond. • Highly reactive element found mostly on earth as a part of water compound

24. C. The Halogens • These include bromine, iodine, fluorine, chlorine, and astatine. Group 17. • A salt forms when a halogen gains one electron from a metal.

25. 2. Uses of Halogens • Chlorine- disinfectant and bleach • Bromine- dyes in cosmetics • Iodine- hormone regulation and disinfectant

26. 3. Sublimation • When a solid changes directly into a gas without first becoming a liquid.

27. Science Warm-up 9/24/2013 • Complete the following Venn diagram comparing and contrasting metals and nonmetals. 1 2 3

30. D. The Noble Gases • These gases exist as isolated, stable atoms. • Their outer electron shell is completely full. • Group 18

31. Section 3: Mixed Groups • Goals • Distinguish among metal, nonmetals and metalloids. • Describe the nature of allotropes. • Recognize the significance of differences in crystal structure of carbon. • Understand the importance of synthetic elements.

32. A. Properties Of Metalloids • Form ionic and covalent bonds • Have some metallic and some non metallic properties • Partial conduction gives them semiconductor characteristics.

33. B. The Boron Group • This group is named for the first element of group 13. • Boron is used in water softening products, antiseptics, and fuels. • Aluminum is abundant in the earth’s crust and very widely used. • This groups is characterized by having 3 valence electrons.

35. C. The Carbon Group • This group is characterized by having 4 valence electrons. • Carbon is found in coal, oil, natural gas, and foods. • If a substance or molecule has carbon that molecule is considered organic.

36. Silicon occurs as an allotrope • Same element with different molecular structures • Silicon found in sand rocks and soil. • The main component in semiconductors, which conduct electricity under certain conditions. • Germanium- also used in semiconductors

37. Tin- used to coat other metals • Lead- toxic, so no longer used in paint • Diamonds, graphite, and buckminsterfullerene are all allotropes of carbon.

38. D. The Nitrogen Group • Characterized by 5 valence electrons, and a tendency to form covalent bonds. • Nitrogen- used to make nitrates and ammonia. Also, one of the main parts of fertilizer. • Phosphorous- used in water softeners, fertilizers, match heads, and fine china. • Antimony and bismuth used with other metals to lower their melting points.

39. E. The Oxygen Group • This group is characterized by having 6 valence electrons. • Oxygen • Makes up 20% of air • Is used by living things in respiration • Provides protection from suns radiation (ozone)

40. Sulfur- used to form sulfide for pigments in paint • selenium- used in photocopiers and multivitamins • Tellurium and polonium are also oxygen group elements.

41. F. Synthetic Elements • Scientists create elements not usually found on Earth. These elements usually degrade quickly. • Uranium can be made into neptunium which forms plutonium when it disintegrates. • Plutonium can be changed into americium, which is used in smoke detectors.

42. 3. Transuranium elements have more than 92 protons and are synthetic and unstable. • The study of synthesized elements helps scientists to understand the forces holding the nucleus together. • Element 114 lasted 30 seconds • It combined 114 protons with 175 neutrons • It broke apart due to enormous repulsion between the protons.

43. Poster Requirements • Group name • Group number • Electron dot diagram (one element) • Atomic structure (one element, cant be same as #3) • Elements included in group • Common uses of elements • Typical bonds made (covalent vs ionic) • Coherent design • Use of color