3 CHEMICAL ELEMENTS 1. Learn the names of elements in English https://www.webelements.com/ Go to this source or find a different website with a ‘talking periodic table’. 2. Name chemical elements. Complete the gaps in the following list. silver Ag Al argon Ar As barium Ba B bromine Br carbon C Ca chlorine Cl chromium Cr Cu F iron Fe hydrogen H helium He Hg I K lithium Li magnesium Mg manganese Mn N Na neon Ne nickel Ni oxygen O P Pb sulphur S Si tin Sn xenon Xe W zinc Zn 3. Work in small groups to answer these questions: a) What elements are present in the air? Do you know the percentages? b) Which element is used as rocket fuel and as alternative fuel for cars? c) What elements are present in the human body? d) Do you know any alloys (combinations of metals)? Which ones? What metals are they made of? e) Which elements can be dangerous? How are they dangerous? 4. What do you know about arsenic? Watch the video and then complete the missing parts in the summary of the uses of arsenic. ^ https://www.youtube.com/watch?v=a2AbKwAvyos Vocabulary: sample (n) - vzorek dispose of (v+prep) – zbavit se mould (n) – plíseň feed livestock (v) – krmit dobytek volatile (adj) – těkavý powder (n) – prášek damp (adj) – vlhký poisonous (adj) - jedovatý vial (n) - lahvička In the past, arsenic used to be …………………………………. than it is nowadays. In the 19^th century, it was used as a …………………………………………..………. which contained copper arsenite. When the rooms in Victorian houses were damp, …………………………………… ………………… converted arsenic into volatile compound and several people …………………….………………….. Because arsenic is toxic, people used it widely ……..…………………………… their business partners, husbands, wives and lovers. Now it is used in ………………………………………… for getting electronic properties of transistors. Sometimes it is still used as medication for ………….………………… or …………………………. . 5. Comparing the properties: Circle the best answer according to the chart. 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 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 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 6. Study the language structures for comparing. Complete the missing words from 1 to 7 below. SIMILAR TO THE SAME DIFFERENT MODIFIER (informal) MODIFIER (formal) comparable identical not so/as …as a bit denser slightly denser like equal whereas a lot more corrosive much more corrosive is as …as differ way higher considerably higher both … and in contrast to significantly higher SHOWING SIMILARITIES Magnesium is like as important as similar to 1 ___________ to aluminium. The properties of these metals are 2________ / the same. similar / comparable. Magnesium resembles parallels aluminium in many ways. 3_________ carbon dioxide and hydrogen are gases. Carbon dioxide and hydrogen are both gases. SHOWING DIFFERENCES Iron is different from 4___________ from aluminium. Iron is (far / much) heavier than less expensive than not as soft 5______ aluminium. Unlike iron, Compared to iron, In 6_____________ to iron, aluminium is light. Iron is heavy, whilst / while/7____________ aluminium is light. Iron is a relatively comparatively soft metal. 7. Write a short paragraph comparing these metals. 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 8. HOMEWORK The Wonder Metals Read the text and find the answers to the questions: 1. Which metals are considered “wonder metals”? 2. What is the chemical substance called fool’s gold? 3. What are the most common alloys formed with iron? 4. What is the advantage of aluminium over iron? 5. Where does magnesium occur? 6. Which elements react violently with water? 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. Complete the gaps with these forms of adjectives: lighter stronger more chemically active more resistant to corrosion less abundant the most widely used more durable Revise comparative and superlative adjectives http://learnenglish.britishcouncil.org/en/english-grammar/how-form-comparative-and-superlative-adje ctives https://www.englisch-hilfen.de/en/exercises/adjectives_adverbs/adjectives_comparison_as_as.htm Sources Zimmerman, F.: English for Science, Prentice Hall, Inc., London