7. COMPARING THE ELEMENTS BRAINSTORMING 1. In groups, find the similarities and differences between the words in pairs. enthusiastic student - bored student dolphin – submarine Adam – Eve 2. What can you compare in chemistry? 3. What skills do you use when you compare? Observation, data collection evaluating differences Recognizing similarities Seeing subtle differences between similar objects COMPARING SKILLS for understanding properties of objects classifying objects LISTENING FOR NUMBERS- Abundance of the most common elements by mass.^1 1. Listen to the recording and note down the elements and the figures (percentages). Reading numbers: 0.05 %: nought point nought five percent, 50-60 %: fifty to sixty percent Earth´s crust Element % Sea Water Element % Whole Earth Element % 2. Look at the figures and write sentences comparing the occurrence of the elements. Use the following expressions: slightly more than far more than a bit less than much less than not as much …as… Other examples: In the Earth´s crust there is much more oxygen than aluminium (not as much Al as O). In sea water we can find slightly less sulphur than magnesium. DESCRIBING SIMILARITIES AND DIFFERENCES The Physical Properties of Six Metals Metal Specific Gravity Melting Point (°C) Boiling Point (°C) Atomic Radius (Å) Ionic Radius (Å) Group I Copper Silver Gold 8.9 10.5 19.3 1083 960 1063 2595 2212 2966 1.17 1.34 1.34 .96 1.26 1.37 Group II Zinc Cadmium Mercury 7.14 8.65 13.60 420 321 -38.87 907 765 357 1.25 1.41 1.44 .74 .96 1.1 1. Circle the answer that best completes the statement according to the information in the chart. a) The atomic radius of cadmium is …………………… that of mercury. 1. as high as 2. not as high as b) ……………………….. mercury, cadmium has a high boiling point. 1. Like 2. Compared to c) The specific gravity of cadmium and copper are ……………………………. . 1. similar 2. identical d) Compared to the other metals in this table, gold has ………………… specific gravity. 1. a relatively high 2. the highest e) The properties of cadmium and zinc are …………………… . 1. comparable 2. identical f) Copper and gold have ……………………. high boiling points. 1. comparatively 2. equally (=identically) g) The melting points of the Group II metals are …………………. those of Group I. 1. lower than 2. as low as h) The ionic radius of copper is …………………….. to that of cadmium. 1. similar 2. equal 2. Speaking Work in pairs and describe this table as a part of your presentation Do not describe every number. You need to look at the important trends or characteristics and give a comparison or general overview. Use the typical phrases, for example: This is a table which shows … As you can see on the left side of the table, … The top row shows… / refers to …/specifies OK. Let’s take a look at … The first / second / next / column – row shows WRITING SHOWING SIMILARITIES A is like as important as similar to comparable to B.. The properties of these metals are equal / identical. similar / comparable. A resembles parallels B in many ways. Both carbon dioxide and hydrogen are gases. Carbon dioxide and hydrogen are both gases. SHOWING DIFFERENCES X is unlike is different from differs from Y. X is (far/much) heavier than less expensive than not as soft as Y. Unlike X, In contrast to X, Compared to X, In comparison to X, Y is light. X is heavy, whereas / while/whilst Y is light. X is a relatively comparatively soft metal. Write a paragraph comparing these metals. Use some of the sentence structures mentioned above. atomic weight occurrence on the Earth density corrosion resistant aluminium 26.982 crust 2.70 g/cm^3 yes iron 55.845 core, crust 7.87 g/cm^3 no magnesium 24.305 crust, sea water 1.74 g/cm^3 no READING THE WONDER METALS Vocabulary: make a discovery (v+n) – učinit objev stainless steel (adj+n) – nerezová ocel all but 20 – všechny kromě 20 cast iron (adj+n) – litina rarely (adv) – málokdy, zřídka abundant(adj) /abundance(n) – hojný/hojnost extract (v) – vytěžit, extrahovat emerge (v) – objevit se major component (adj+n) – hlavní složka supply (n) – zásoba remain (v) – zůstávat, zbývat withstand heat (v+n) – odolat teplu 1. Read the text and complete the gaps with these forms of adjectives: lighter, stronger, more chemically active, more durable, more resistant to corrosion, less abundant the most widely used The study of metals began in the Middle Ages when alchemists searched for a technique to convert “base metals”, like lead, to gold. They never succeeded in making gold but at least by experimenting with the metals (in contrast to the ancient Greeks, who only speculated about them) they made discoveries. All but 20 of the over 100 elements identified to date are metals but only 7 of these are common in the earth´s crust. Iron, 1____________metal, is rarely found in the free state (not combined with other metals) and must be extracted from naturally occurring compounds (ores) such as hematite, magnetite, and pyrite. The beautiful colors of rocks are due to these iron compounds. In fact, iron pyrite is often called fool´s gold because of the similarity of its color to gold. Iron is very strongly magnetic, and the fact that the earth is a magnet itself tipped scientists off to the fact that iron is a major component of the earth´s core, or centre. Pure iron is a relatively soft, silvery metal that is very active chemically (that is, it combines with oxygen to corrode or form rust). It is usually mixed with other elements or compounds to form alloys such as steel, stainless steel, or cast iron, which are 2_____________ and rust resistant than pure iron. Aluminum is the most abundant metal, but it was not used until a century ago because it is so active chemically and difficult to extract. Like iron it is soft, but in contrast to iron and steel, aluminum is very light and 3______________. These qualities make it useful for airplanes, trains, automobiles, and rockets. In the 1940s, magnesium emerged as an important metal. Although it is 4___________ in the earth, 5______________, and harder to extract than aluminum, it is present in sea water and that means there is almost an endless supply of it. In the space age, the extraordinary properties of titanium have made it the new wonder metal. 6____________and 7___________than steel, it is more resistant to corrosion and able to withstand heat. The remaining major metals are sodium, potassium, and calcium, all too active chemically (they react violently with water) for use in construction. 2. Speaking. Discuss these questions in pairs: 1. Did alchemists contribute to the progress of chemistry? How? 2. How can iron be obtained? obtain = získat 3. How do we know that iron is in the Earth’s core? 4. How are the iron alloys different from iron in properties? 5. What are the advantages of Al over Fe? 6. Which metal is stronger than steel? 3. Test your vocabulary. Which words go to these phrases from the reading? 1. succeeded ……….. making gold 2. they ……….. discoveries 3. all ……….. 20 4. such ……….. hematite, magnetite, and pyrite 5. similarity of its color ……….. gold 6. Al is difficult ………..extract 7. in contrast ……….. iron 8. Mg emerged ……….. an important metal 9. able to ……….. heat 10. react ……….. with water Names of chemical elements Listening. Listen to the song of the elements by Tom Lehrer and fill in the gaps. Available at http://www.privatehand.com/flash/elements.html , Transcript http://www.edu- cyberpg.com/iec/elementsong.html^ ^ There’s antimony, arsenic, aluminum, selenium, And hydrogen and and nitrogen and rhenium. And nickel, neodymium, neptunium, germanium, And , americium, ruthenium, uranium, Europium, zirconium, lutetium, vanadium, And lanthanum and osmium and astatine and _____________ . And gold, protactinium and indium and gallium, And and thorium and thulium and thallium. There’s holmium and helium and hafnium and erbium, And and francium and fluorine and terbium. And manganese and mercury, molybdenum,_____________________ Dysprosium and scandium and cerium and cesium, And lead, praseodymium, and platinum, plutonium, Palladium, promethium, polonium, Tantalum, technetium, titanium, tellurium, And cadmium and and chromium and curium. There’s yttrium, ytterbium, actinium, And boron, gadolinium, niobium, iridium. And strontium and and silver and samarium, And bismuth, bromine, lithium, beryllium and barium. There’s sulfur, californium and fermium, berkelium, And also mendelevium, einsteinium and nobelium. And argon, , neon, radon, xenon, zinc and rhodium, And chlorine, carbon, cobalt, copper, Tungsten, tin and . These are the only ones of which the news has come to Harvard, And there may be many others but they haven’t been discovered. ^ ^ ^ ^ ^ ^ ^ HOMEWORK Complete the gaps in the following list of common chemical elements. Al gold Au oxygen O argon Ar He P barium Ba hydrogen H platinum Pt beryllium Be I K B iron Fe Si bromine Br Pb silver Ag Cd lithium Li Na Ca Mg strontium Sr carbon C manganese Mn S Cl Hg tin Sn chromium Cr neon Ne W Cu Ni xenon Xe fluorine F N Zn GRAMMAR Použijte slov v závorkách a dokončete věty. Použijte much / a bit + druhý stupeň, popř. than: 1. Her illness was much more serious than we thought at first. (much / serious) 2. This bag is too small. I need something ................................................... (much / big) 3. I´m afraid the problem is ................................................ it seems. (much / complicated) 4. You looked depressed this morning but you look ...................................................... now. (a bit / happy) 5. I enjoyed our visit to the museum. It was ....................................................... I expected. (far / interesting) d) Dokončete věty, použijte as......as: 1. I´m quite tall but you are taller. I´m not as tall as you. 2. My salary is high but yours is higher. My salary isn´t ..................................................... 3. You know a bit about cars but I know more. You don´t .................................................. 4. It´s still cold but it was colder yesterday. It isn´t ............................................................. e) Vytvořte věty, kde použijete the same as: 1. Sally and Kate are both 22 years old. Sally is the same age as Kate. 2. You and I both have dark brown hair. Your hair ............................................................. 3. I arrived at 10:25 and so did you. I .................................................................................. 4. My birthday is 5 April. Tom´s birthday is 5 April, too. My ............................................ f) Dokončete věty. Použijte than.... nebo as .......: 1. I can´t reach as high as you. You are taller than me. 2. He doesn´t know much. I know more ....................................................................... 3. I don´t work particularly hard. Most people work as hard ....................................... 4. We were very surprised. Nobody was more surprised ............................................. Sources: Lesson based on Zimmerman, F.: English for Science, Prentice Hall, Inc., London, 1989. ^1Bates, Martin and Dudley-Evans, Tony: Nucleus of General Science. Longman 1990. Unit 9, Listening Practice 1. ^3 Raymond Murphy: English Grammar in Use second edition, Cambridge University Press 1994. Hana Němcová, English for Biologists