With the STUDY NOTES you can revise the key concepts of each unit and check your progress. C O N C E P T M A P > Copy and complete the concept map. particles … : negatively charged protons: … charged … : not charged S U M M A R Y representation definition types of radiation the nucleus of an … atom decays and emits very … radiation ATOM ATOMIC MODELS RADIOACTIVITY A Z X isotopes A: … X: symbol of the element Z: atomic number Dalton (1803) … reactions fission: nuclei break apart … : nuclei join together … (1904) Rutherford (1909) … (1913) indivisible particles: … positively charged sphere with … charged electrons … in the nucleus and electrons orbiting it … model electrons move around the nucleus in orbits, layers or … levels … model ions atoms with the same number of … and a different number of … atom loses electrons atom gains electrons positive ion or … negative ion or … … particles ß particles X-rays … rays … 19 4 ES0000000149816 223258_Unidad04_112065.indd 19 18/7/22 13:37 o r g a n i s e yo u r i d e a s 3 c h e c k yo u r p r o g r e s s 50 TA B L E . Complete the table in your notebook by putting the data below in the correct boxes. Proton Electron Neutron Mass 1.673 · 10–27 kg ... ... Charge ... ... ... -1.6 ? 10-19 C +1.6 ? 10-19 C 0 C 9.11 ? 10-31 kg 1.675 ? 10-27 kg Then complete another table like the one above. Indicate the value of the mass and the charge in atomic units. 51 D R AW I N G . The diagrams below represent the two atomic models that we studied in this unit. Draw and label them in your notebook. Shell Layers model Proton Electron Layer Neutron Nucleus Planetary model 52 D I A G R A M . We use the symbol A ZX to represent an atom. Complete the diagram in your notebook. 235 92U ... ... ... Then complete these sentences. a) The number of protons is given by … . b) The number of electrons is given by … . c) The number of neutrons is given by … . 53 D I A G R A M Complete this diagram comparing the two isotopes of copper, 63Cu and 65Cu, in your notebook. 65Cu 63Cu ... ... Z ... ... A ... ... No. of neutrons ... ... No. of protons ... ... No. of electrons 54 D I A G R A M Complete this diagram in your notebook. It gains electrons ... ... ... ... Cation Atom 55 DIAGRAM Compare nuclear fission and nuclear fusion and write the differences between them in your notebook. ... Fusion ... ... ... Fission ... ... Definition Energy generation Waste generated What atoms are like 56 St. Peter’s Basilica in Rome is the largest temple in Christianity. Its dome has an internal diameter of approximately 40 m. Imagine an atom the size of this dome. Which of these objects are comparable in size to its nucleus? 57 Analyse these sentences. Write in your notebook the one that explains why we say that most of an atom is empty. a) Electrons are much smaller than protons. b) The nucleus of an atom is much smaller than the atom. c) Atoms are very small structures. 58 What mass will a sodium (Na) atom have if it is made up of 11 protons, 12 neutrons and 11 electrons? 59 Look at the diagrams of these atoms and complete the table below: Atom Number of layers Number of electrons per layer Total number of electrons O ... ... ... Na ... ... ... P ... ... ... S ... ... ... 60 Draw the layers model of an atom of these elements: nitrogen, aluminium, calcium and neon. 61 An atom has 53 protons and 74 neutrons. a) What is its atomic number? And its mass number? b) Use the periodic table in the annex to find which chemical element it belongs to. What is its symbol? 62 Draw a diagram of these atoms. Show all the particles and where they are located. a) 14 6 C b) 14 7 N 63 Analyse the drawings below that represent these atoms and complete the diagram in your notebook. Beryllium Boron B Be ... ... No. of electrons ... ... No. of neutrons ... ... Atomic number: Z ... ... Mass number: A ... ... No. of protons Lithium Helium S O LV E D P R O B L E M 3 Draw a diagram of these atoms, showing all the particles and where they are located. 4 2He 7 3Li 1. Identify the particles in each atom. Remember what A ZX means. X: name Z: no. of protons No. of electrons A - Z: no. of neutrons Helium 2 2 4 - 2 = 2 Lithium 3 3 7 - 3 = 4 2. Draw the atoms: a) In the nucleus, draw the protons (in red) and the neutrons (in green). b) In the shell, in layers, draw the electrons (in blue). Keep in mind the number of electrons that can be in each layer. Place the third electron in the second layer, as only two electrons fit in the first layer. Model: ... C A B E D Model: ... C A B E D Sulphur (S) Oxygen (O) Sodium (Na) Phosphorus (P) Basketball (24 cm diameter) Ping pong ball (4 cm diameter) Pearl (4 mm diameter) Use the STUDY NOTES to review the content of this unit. 103 102 ES0000000137418 183391_Unidad04_111062.indd 102-103 18/7/22 13:32 Ac t iv it y wr i s tbands Few people could have predicted the success of these devices a few years ago. Is there any athlete who does not have a smart watch or wristband now? The beginnings were not at all easy. Fitbit only had two employees during its first three years and failed to make a profit until the fourth year. “On the day of the demo, when we launched the first product, someone asked me how many people had reserved one. I replied there were only five people. I was told that was quite pessimistic,” Fitbit CEO James Park remembers. www.itespresso.es (Adapted) In 2007 the first activity wristband was released by the company Fitbit. Activity wristbands are fitted with various sensors. These allow the wristband to collect dif ferent types of data . Then this is processed to give you appropriate suggestions through an app. ▶ How do wristbands count steps? Most wristbands include sensors called accelerometers that can measure movement. Normally, accelerometers have three axes that allow them to sense movement in all directions. ▶ How do wristbands measure height? An altimeter sensor determines the height of a mountain you have climbed . This sensor tells you how many steps you have climbed up or down in a day. ▶ How do wristbands know how I sleep? They use sensors that can track wrist movements. When we sleep, the horizontal position of the body is interpreted as the initial stage of sleep. Our heart rate slows down , blood pressure decreases, muscles relax and we move less. The activity wristband can also detect the drop in heart rate and the lack of wrist movement. ▶ How do wristbands measure my pulse? There are two methods: • Optical sensors. They use sensors that emit continuous beams of light that dif fuse into the skin , lighting up the blood vessels. At the same time, another sensor detects the speed at which blood is pumped by the heart. This system is especially useful when we exercise and our heart rate is ver y easy to detect. • Bioimpedance sensors. They emit electrical impulses that detect the resistance of the skin to these impulses. This resistance is interrupted ever y time the heart beats. This is how the sensor can measure the pulse rate. ▶ How do wristbands measure calories? They use the data collected by the dif ferent motion and temperature sensors. This tells the wristband how many steps we have taken in a day, how many steps we have climbed up or down, and how far we have travelled. Using algorithms, this information is then compared with data previously entered into the wristband, such as weight, height, sex and age. The result is shown as the amount of calories burnt in a day. pulseradeactividad .net (Adapted) > Find information and explain what features a GPS sensor adds to activity wristbands. 4 228729_Innovations Part 1.indd 4 18/7/22 16:07 FINAL ACTIVITIES 5 Study the information and apply your essential knowledge to different contexts and situations. Do the activities in the ORGANISE YOUR IDEAS and CHECK YOUR PROGRESS sections. Critical thinking. Analyse a news article and answer the questions that will help you to think about and show your reasoning. Make connections between Physics and Chemistry and other subject areas to help you understand the world you live in. Complete the challenge and tell other people what you have achieved. Share the results with the people around you. In this way, you are contributing to the construction of a better world for everyone. 76 Nuclear power is said to be a clean energy. What does this mean? Is nuclear waste not a pollutant? 77 The technical staff that do X-rays on patients leave the room just before taking the image. a) Why do you think they do this? b) Could the X-ray machine be kept in a cubicle with wooden walls? 78 Atoms for Peace is the name of a famous conference that was a very important moment in the development of nuclear energy. Form a team and find information to prepare a presentation that shows: a) Who proposed Atoms for Peace? When and where did this happen? b) Before that date, nuclear energy had been used for non-peaceful purposes. What were they? What consequences did they have? c) Make a list of the peaceful uses of nuclear energy. For each one, prepare a summary with their most important applications. 79 Read this article and answer the questions. Nobel Prize winner Gérard Mourou believes that nuclear waste could be made safe in 20 years French Nobel Prize in Physics winner Gérard Mourou , who is working on the development of the most powerful laser in the world , has calculated […] that this application could be used to decontaminate nuclear waste in 20 years. The current experiments with the so-called "extreme light", led by European laboratories, will be able to complete the first tests in this particular application within five or ten years from now. Then it will take ten more years to build the appropriate plants for the treatment of nuclear waste. For the "transmutation" of nuclear waste (removal of radioactivity), this advanced laser will be able to make particles like neutrons more compact "to shorten their harmful lifetime" and reduce the radioactive period from millions of years to just years. This would solve the problem of nuclear energy : the lifetime of toxic waste […]. ecodiario.eleconomista .es 25th May 2019 (Adapted) a) Explain the expression: "to shorten their harmful lifetime". b) Why does the article say "solve the problem of nuclear energy"? What is this problem? c) Can you think of any other areas that could benefit from the technique described in the article? Discuss it in class and write down your conclusions. c h e c k yo u r p r o g r e s s 75 C H E M I S T R Y A N D A R C H A E O L O G Y. Carbon-14 dating is a technique used in archaeology to determine the age of the remains found in excavations. It is based on the decay of C-14 isotopes. C is one of the most abundant elements in living things. While an organism is alive and feeding, the percentage of C-14 in its atoms remains constant. However, when an organism dies, this isotope decays. It is not replaced, so it gradually disappears. It has been observed that every 5 730 years, half of the C-14 atoms in a sample decay and disappear. This period is known as the half-life. a) Assuming that in a sample we have 160 C-14 atoms, calculate how many years it would take to have ten C-14 atoms left. b) Would the C-14 dating technique be useful to determine the age of the remains found in Sima de los Huesos in Burgos, which are about 400 000 years old? Tip: for every 100 C-14 atoms that were present initially, calculate whether there is a significant number of atoms left to analyse the radiation they emit. c) The oldest known rocks have been found in Jack Hills, Australia, and are about 4 billion (4 000 000 000) years old. Would C-14 dating be useful in determining their age with any precision? 106 ES0000000137418 183391_Unidad04_111062.indd 106 18/7/22 13:35 69 Look at the diagrams and identify the atoms and ions they represent. Write their names in your notebook. B A 70 Find the information you need in the periodic table in the annex to complete these sentences in your notebook. a) The symbol for the element chromium is … . The atomic number of chromium is … . This means that all chromium atoms have … protons and, if they are electrically neutral, … electrons. When a chromium atom loses three electrons it acquires a … electrical charge. The chromium atom has become a … ion, or … , and is called a … . b) The symbol for the element sulphur is … . The atomic number of sulphur is … . This means that all sulphur atoms have … protons and, if they are electrically neutral, … electrons. In many compounds, the sulphur atom has 18 electrons. This means it acquires an electric charge of … . The sulphur atom has become a … ion, or … , and is called a … . 71 Complete the table in your notebook. Find the information you need in the periodic table in the annex. Symbol Name P E N Charge A ... Bromide ... ... ... ... B 138 56 Ba 2+ ... ... ... ... ... C ... ... 7 ... 7 3D 83 36 Kr ... ... ... ... ... E 88 38 Sr 2+ ... ... ... ... ... F ... ... 33 ... 75 372 The atomic models you have studied were proposed by men. Today, the role of women in science is just as relevant, as proved by Fabiola Gianotti, the first woman to lead CERN (European Organisation for Nuclear Research), for example. a) Do you think it is important that there are women in charge of scientific institutions? Why? b) Why do you think that most of the discoveries about the structure of atoms were made by men? Radioactivity 73 What type or types of nuclear radiation correspond to each of these characteristics? a) They are electromagnetic radiation. b) They are particles. c) The particles have a mass of 4 u. d) Its electric charge is negative. e) They are particles without a charge. f) It can go through the human body. g) It can go through a lead wall. 74 Which sentences can be applied to the process of nuclear fusion? Which can be applied to nuclear fission? Which are false? Explain in your notebook. a) The particles in the atomic nucleus are broken apart and a large amount of energy is released. b) The particles in the atomic nucleus join together and energy is released. c) The nucleus of the atom is broken into several fragments, releasing a large amount of energy. d) The nuclei of several atoms join together, releasing a large amount of energy. e) The atoms of one element are transformed into atoms of a different element. f) Waste is produced that is very dangerous to our health. 3 J. J. Thomson E. Rutherford F. Gianotti 105 ES0000000137418 183391_Unidad04_111062.indd 105 18/7/22 13:34 80 Prepare a report. Marie Curie received two Nobel prizes: one in Chemistry and one in Physics. Working in pairs, search for information. Highlight her research on radioactivity and the discovery of some chemical elements. Make a poster, report or presentation with your conclusions. 81 Why is radioactive waste dangerous? Choose the correct answer and write it in your notebook. a) Because it is very difficult to recycle it. b) Because it can remain inactive for many years until it starts to emit radiation. c) Because it can emit harmful radiation for hundreds or thousands of years. 82 Ida Noddack and Lise Meitner played an important role in the discovery of nuclear fission. Work in pairs and look for information about these two scientists. Make a presentation that shows: a) The biographical data of each scientist. b) The areas they investigated, as well as their most important findings. c) Their studies on nuclear fission. d) Who received the Nobel Prize for research on nuclear fission. Our first radioactive series Work with your classmates to create the screenplay for your series. Collect some useful diagrams and animations that can be the scientific basis for the screenplay. Draw sketches to represent some key scenes from the start, middle and end of the series. Think: what kind of music would go well with the series? Fast? Calm? Design a poster to promote the series. In the poster, refer to the different atomic models you have studied. Create a #hashtag or tag to promote your series on social media. Show the others a promotional item: bookmarks, a trailer or other things. Create a title and slogan to promote the series. Present the series to your classmates: the main plot, details of the main characters, where it will be set, in which period, etc. As you created the screenplay for the series, you have learnt what atoms are like, why radioactivity exists, the applications of some radioactive isotopes and how radioactive waste should be managed. 3 W E L L D O N E ! Ida Noddack Lise Meitner CHALLENGE 107 ES0000000137418 183391_Unidad04_111062.indd 107 18/7/22 13:51 In addition, there is helpful support material available: A FORMULATION ANNEX at the end of the book will help you to understand and practise chemical nomenclature with activities. A notebook with INNOVATIONS IN SCIENCE helps you to understand the importance of science in our society. THE CHALLENGE 6 2. Binary compounds Annex 1 Binar y compounds resu lt f rom the combinat ion of atoms of t wo chemica l elements. One w i l l have a posit ive ox idat ion number (the electroposit ive element) and the other w i l l have a negat ive ox idat ion number (the electronegat ive element). 2.1. Naming binary compounds Look at how the name of a bina r y compound is formed in t wo d i f ferent ways, using composit iona l nomenclatu re. 2.2. Writing the formula of a binary compound Look at how the formu la of a chemica l compound is formed f rom its name in composit iona l nomenclatu re: Prefixes Dia luminium tr isu lphide AℓS Wr ite the sy mbol of each element in the cor rect order. 1 AℓS Wr ite the sy mbol for each element . The one end ing in –ide w i l l be on the r ight in the formu la . 1 Aℓ2S3 Add the number cor respond ing to the pref i x of each element as a subscr ipt . In th is case, di, 2 for Aℓ and t ri, 3 , for S. 2 Aℓ S Locate the ox idat ion number of the elements in the table: Aℓ, electroposit ive element . Ox idat ion number : +3 S, electronegat ive element . Ox idat ion number : -2 2 Aℓ m Sn m ? (+3) + n ? (-2) = 0 m = 2 n = 3 Aℓ2S3 The sum of the ox idat ion numbers of a l l the elements must be zero for the compound to be neutra l . Find the sma l lest possible subscr ipts to simpl i f y the formu la as much as possible. For example, Aℓ4S6 is a lso va l id , but it shou ld be simpl i f ied . 3 Oxidation numbers A luminium su lphide S O LV E D P R O B L E M 1 Formula Prefixes Oxidation numbers AℓBr3 Aluminium tribromide Aluminium bromide CuCℓ2 Copper dichloride Copper(II) chloride A C T I V I T I E S 1 Name in your notebook: a) PbCℓ2 d) Cr2S3 b) AℓF3 e) Na3N c) BaI2 f ) K2S A C T I V I T I E S 2 Write the formula for: a) Barium chloride b) Tin tetraiodide c) Nitrogen trifluoride d) Mercury dichloride e) Phosphorus pentachloride f ) Iron(III) sulphide g) Cobalt(II) bromide h) Aluminium nitride S O LV E D P R O B L E M 2 Write the formula for these compounds. a) Barium dichloride b) Iron(III) iodide a) On the right, write the symbol of the element ending in -ide: chlorine. Add the subscript, 2, corresponding to the numerical prefix of chlorine, di: BaCℓ2 b) On the right, write the symbol of the element ending in -ide: iodine. To the iodine symbol, add the subscript indicating the oxidation number of iron, which is given by the Roman numeral: FeI3 Look up the ox idat ion number of the electroposit ive element in the table. Wr ite it in Roman numera ls inside brackets a f ter the posit ive element's name, w ithout leav ing a space. I f the element on ly has one ox idat ion number, it is not added to the name. dialuminium trisulphide sulphur tetrachloride aluminium sulphide sulphur(IV) chloride The name of each element is preceded by a pref i x that ind icates the number of atoms of th is element in the formu la : mono, for one. The pref i x mono can be omit ted i f there is no conf usion. di, for t wo. t ri, for three. tet ra, for fou r. penta, for f ive. hexa, for si x , etc. name of the element on the left + name of the element on the right + -ide Using prefixes Using oxidation numbers Look at these examples: Note that S is named after its Latin origin, sulphur. Aℓ only has one oxidation number, so it is not added. element acting as electronegative element acting as electropositive The negative oxidation number of Cℓ is -1. For the compound to be neutral, S must act with its oxidation number +4: +4 + (-1) ? 4 = 0 Element on the right: sulphide Element on the right: chloride Element on the left: aluminium Element on the left: sulphur Aℓ2S3 SCℓ4 The elements combine in a propor t ion that resu lts in a neutra l compound. That is, the sum of the oxidation numbers of all the elements in the formu la must be zero. +3 -2 +3 -2 293 292 ES0000000137418 183391_ANEXOS_115340.indd 292-293 18/7/22 13:36
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