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1 CHAPTER 2:THE STRUCTURE OF THE ATOM 2.1 MATTER: (refer text book pg 11) 1. Particle Theory of Matter : Matter is made up of …………………… and ……………….. particles. 2. The tiny particles may be atoms, ……………….. and ………………………. 3. Kinetic Theory of matter : Matter consists of small particles that always collide among each other. The particles move faster when energy is ……………… and slower when they are …………. 4. Change of states of matter based on Kinetic Theory: State of matter Solid Liquid Gas Particles The particles are The particles are The particles are arrangement …………….together ………… but not in …………….. apart from in an ……………. …………. each other. Particles can only Particles can ………, Particles can …………., …………..and …….. ………… and ………. ……………… and About their fix throughout the liquid ……… freely Draw the particles arrangement manner Particles movement positions Attractive forces Very …………………, Strong ……………… …………………. Forces between the …………….. between between particles but between particles particles particles then the forces in solid. Kinetic energy of particles …………………….. ………………………. 1 ……………………… 2 5. When heat energy is supplied to particles in matter, its kinetic energy (increased/decreased) and the particles in matter vibrate ( faster/ slower) When matter loses heat energy, the kinetic energy of the particles (increased/decreased) and they vibrate ( faster/ slower). 6. ( A ) ( SOLID B ) LIQUID ( C ) GAS ( D ) A …………………… B ……………………… C…………………… D……………………. 7. The temperature at which a ………………………………. Completely changes to become a liquid is called ……………………………….. 8. Explanation on the heating process of matter (refer text book 15) Temperature OC D B C A point Times/s States of matter explanation A to B B to C C to D 2 3 9. Explanation on the cooling process of matter Temperature OC A B C D Times/s Point State of matter Explanation P to Q Q to R R to S Freezing point : The temperature at which a …………………… changes into ……………. During the freezing process, the temperature remains unchanged because the heat lost to the environment is ………….. by the heat released when the liquid particles rearrange themselves to become solid. 3 4 2.2 THE ATOMIC STRUCTURE The Historical Development Of Atomic Models Complete all the blanks and draw the structure of each atomic model. Model Structure Characteristic Dalton’s atomic model (proposed by ………………in …………) The atom was imagined as a small indivisible ball similar to a very tiny ball. J.J Thomson discovered the………., a negatively-charged particle. The atom was describe as a sphere of positive charge embedded with electrons. Thomson’s atomic model (proposed by ……………… in………..) Ernest Rutherford discovered ………, a positively-charged particle in an atom. The central region of atom has a very small positively-charged ……………, which contains almost all the mass of the atom. Rutherford’s atomic model (proposed by ………………… in ……….) The electrons in an atom move in ………… around the nucleus which contains protons. Bohr’s atomic model (proposed by ……………… in ………..) Chadwick proved the existence of ……………., the neutral particle in the nucleus. The nucleus of the atom contains protons & neutrons, and the nucleus is surrounded by electrons. …………… contribute approximately to half the mass of an atom. Chadwick’s atomic model (proposed by …………..……. in ……….) 4 5 Subatomic Particle Of An Atom Fill all the blanks and complete the table. (refer text book pg 18) 1. Atoms are made up of subatomic particles namely …………….., …………… and ………….. ………….. and …………….. are found in the nucleus of an atom while electrons surround the nucleus. Subatomic particle Symbol Relative mass Relative electric charge Proton Neutron Electron 2. The proton number of an element is the number of ………………… in its atom. PROTON NUMBER, Z = NUMBER OF. PROTON 3. Protons and neutrons are collectively called nucleons. The nucleon number of an element is the total number of ……………… and …………….. in its atom. NUCLEON NUMBER, A = NUMBER OF. PROTON + NUMBER OF NEUTRON 4. The nucleon number is also known as the mass number. NUMBER OF NEUTRON = NUCLEON NUMBER -- PROTON NUMBER = A -- Z 5. Symbols Of Elements The standard representation for an atom of any element shows the proton number and the nucleon number of the element. It can be written as follows: A Z # X A – Nucleon number Z – proton number X – symbol of element 5 6 1 H 1 3 Li 7 21 Sc 45 Proton number Nucleon number 2 He 4 4 Be 9 5 B 11 6 C 12 7 N 14 8 O 16 9 F 19 10 Ne 20 11 12 Na Mg 23 24 13 Al 27 14 Si 28 15 P 31 16 S 32 17 Cl 35 18 Ar 40 19 K 39 20 Ca 40 21 Sc 45 Consider part of the periodic table of the element above and complete the table below. Element Symbol Proton number No. of electron Scandium Aluminium Argon Beryllium Boron Calcium Carbon Chlorine Fluorine Helium Hydrogen Lithium Magnesium Neon Nitrogen Oxygen Phosphorus Potassium 6 Nucleon number No. of neutron Standard representation 7 2.3 ISOTOPES AND THEIR IMPORTANCE 2.1 Isotopes And Their Importance ( refer text book pg 20) ** Isotopes are atoms of the same element with different numbers of neutrons. Complete the table: Element Hydrogen Oxygen Number of isotopes 3 3 Symbol of isotopes H Number of protons 1 H 1 H 1 O 8 1 1 1 1 1 1 16 8 Number of electrons Number of neutrons Name of isotopes Hydrogen-2 8 8 9 6 7 8 Oxygen-16 18 8 O Carbon 6 6 3 Carbon-12 14 6 C Chlorine Bromine 2 35 17 Cl 2 * Uses of isotopes in Our Daily Lives 17 17 35 35 20 35 Bromine-80 Bromine-81 (refer text book pg 21) 1. Cobalt-60 : _____________________________________________________ . 2. Gamma rays of Cobalt-60 : ________________________________________ 3. Carbon-14 : ______________________________________________________ 4. Phosphorus-32 : __________________________________________________ 2.4 THE ELECTRONIC STRUCTURE OF AN ATOM 1. The elektron are filled in specific shells. Every shell can be filled only with a certain number of electrons. For the elements with proton number 1-20:First shell can filled with a maximum of ……………. electrons Second shell can filled with a maximum of ……………. electrons Third shell can be filled with a maximum of …………….electrons 7 8 Third shell filled with 8 electrons Second shell filled with 8 electrons First shell with 2 electrons Lithium Atom Number of proton 1 x Li x 3 Number of electron Number of neutrons Proton number Nucleon number x Electron arrangement Sodium Atom x Na x x 11 x x x Number of proton 23 Number of electron Number of neutrons x Proton number x Nucleon number Electron arrangement x x x x 2. Valance electron : Electron in the …………………. shell of a neutral atom. 8 9 CHAPTER 3: CHEMICAL FORMULAE AND EQUATIONS 3.1 RELATIVE ATOMIC MASS (RAM) AND RELATIVE MOLECULAR MASS (RMM) Relative atomic mass of an elemant , Ar = The average mass of an atom of the element 1/12 x the mass of an atom of carbon-12 Example: Ar of C=12 Ar of O=16 Ar of Mg=24 Relative molecular mass of a substance, Mr = The Average mass of a molecule of the substance 1/12 x the mass of an atom of carbon-12 Calculating Relative molecular mass,Mr Mr= The sum of Ar of all atoms present in one molecule Example: 2 Hydrogen atoms Molecular formula Mr of Water, H2O = 2(1) + 16 = 18 Relative atomic mass for Oxygen Relative atomic mass for Hydrogen Mr of Carbon dioxide, CO2 = 12 + 2(16) = 44 For ionic substance , Relative formula mass , Fr = The sum of Ar of all atoms present in the formula All Ar, Mr and Fr have no unit Example: Fr of Magnesium oxide, MgO = 24 + 16 = 40 Fr of Sodium chloride, NaCl = 23 + 35.5 = 58.5 1. Calculate the Relative molecular masses of the substances in the table below. Substance Molecular formula Relative molecular mass, Mr Hydrogen gas H2 2(1) = 2 Propane C3H8 9 10 Ethanol C2H5OH Bromine gas Br2 Methane CH4 Glucose C6H12O6 Ammonia NH3 [Relative atomic mass : H,1; C,12; O,16; Br,80 ; N,14 ] 2. Calculate the relative formula masses of the following ionic compounds in the table. Substance Compound formula Relative formula mass, Fr Potassium oxide K2O 2(39) + 16 = 94 Aluminium sulphate Al2(SO4)3 2(27)+3[32+4(16)]=342 Zinc nitrate Zn(NO3)2 Aluminium nitrate Al(NO3)3 Calcium carbonate CaCO3 Calcium hydroxide Ca(OH)2 Hydrated copper(II) sulphate CuSO4.5H2O Hydrated sodium carbonate Na2CO3.10H2O 64 + 32 + 4(16) + 5[2(1) + 16]=250 [Relative atomic mass: O,16; C,12; H,1; K,39 ; Cu,64 ; Zn, 65; Cl, 35.5 ; Al, 27 S,32 ; Ca, 40; Na,23; N, 14] 10 11 3.2 The Mole and the number of particles 1. To describe the amount of atoms, ions or molecules , mole is used 2. A mole is an amount of substance which contains a constant number of particles (atoms, ions, molecules which is 6.02 x 1023 3. The number 6.02 x 1023 is called ………………………….. (NA) 4. relationship between number of moles and number of particles (atom/ion/molecules): x Avogadro Constant number of moles number of nmolecules ∻ A vogadro Constant Number of moles ………….. mol of carbon atoms Number of particles 3.01 x 1023 atoms of carbon 0.2 moles of hydrogen gas (i) (ii) ………………… mol of carbon dioxide molecules …………….. molecules of hydrogen ……………. Atoms of hydrogen 6.02 x 10 23 molecules of carbon dioxide contains : …………atoms of C and ……. Atoms of O 3.3 Number of Moles and Mass of Substances 1. Molar Mass : (a) Molar Mass is the mass of one mole of any substance. (b) Molar Mass is the relative atomic mass, relative molecular mass and relative formula mass of a substance in g mol -1 (c) Molar Mass of any substance is numerically equal to its relative mass. X RAM/RMM/RFM Number Of moles Mass in g ∻ RAM/RMM/RFM 11 12 2. Complete the following table. Element/compound Copper Chemical formule Cu RAM/RMM/RFM RAM= 64 Calculate (a)Mass of 1 moll (b) Mass of 2 mol : (c)Mass of ½ mol: (d)Mass of 3.01x1023 Cu atoms: Sodium hydroxide NaOH RFM= 40 (a) Mass of 3 mol of sodium hydroxide (b) Number of moles of sodium hydroxide in 20 g Zinc nitrate Zn(NO3)2 RFM = a) Number of moles in 37.8 g of zinc nitrate: 3.4 Number of Moles and Volume of gas 1. Molar volume of a gas : Volume occupied by one mole of any gas. 2. The molar volume of any gas is 24 dm3 at room conditions and 22.4 dm3 at standard temperature and pressure (STP) 3. generalization : One mole of any gas always occupies the same volume under the same temperature and pressure; Example i) 1 mol of oxygen gas, 1 mol of ammonia gas, 1 mol helium gas and 1 mol sulphur dioxide gas occupies the same volume of 24 dm3 at room condition 12 13 x 22.4/24 dm3 Number of moles of gas Volume of gas ∻22.4/24 dm3 Volume of gas (dm3) Mass in gram Number of moles No of particles Complete the above diagram (Refer to Page 33,34 & 38-Chemistry textbook) Relative Atomic Mass : Fe = 65, Ca = 40, Cl = 35.5, Mg = 24, H = 1, O = 16, C =12 Avogadro number = 6 x 1023, The Molecules and the Volume of Gas 1. What is the volume of 0.3 mole of sulphur dioxide gas at STP? [Molar volume: 22.4 dm3 mol-1 at STP] (Ans: 6.72 dm3) 2. Find the number of moles of oxygen gas contained in a sample of 120 cm3 of the gas at room conditions. [Molar volume: 24 dm3 mol-1 at room conditions] (ans: 0.005 mol) 13 14 3. Calculate the number of water molecules in 90 g of water. [Relative atomic mass: H, 1; O, 16. Avogadro constant, NA: 6.02 x 1023 mol-1] (Ans; 3.01x 1024 molecules) 4. What is the volume of 24 g methane at STP? [Relative atomic mass: H, 1; C, 12. Molar volume: 22.4 dm3 mol-1 at STP] (Ans: 33.6 dm3) 5. How many aluminium ions are there in 20.4 g of aluminium oxide? [Relative atomic mass: O, 16; Al, 27. Avogadro constant, NA: 6.02 x 1023 mol-1] 6. Calculate the number of hydrogen molecules contained in 6 dm3 of hydrogen gas at room conditions. [Molar volume: 24 dm3 mol-1 at room conditions Avogadro constant, NA: 6.02 x 1023 mol-1] 7. Find the volume of nitrogen in cm3 at STP that consists of 2.408 x 1023 nitrogen molecules. [Molar volume: 22.4 dm3 mol-1 at STP. Avogadro constant, NA: 6.02 x 1023 mol-1] (2 x 0.2 x 6.02 x1023) (Ans: 1.505x1023 molecules) (Ans: 8.96 dm3 ) 14 15 3.5 CHEMICAL FORMULAE 1. Chemical formulae- A set of chemical symbols for atoms of elements in whole numbers representing chemical substances. Chemical subtance Chemical formulae Notes ------------- 2 atoms of H combine with 1 atom of O ------------ NH3 ----- atoms of H combine with 1 atom of N Propene C3H8 3 atoms of C combine with ----- atom of H Water 1. There are two types of chemical formulae ** Empirical Formula ** Molecular Formula Molecular formula = (Empirical formula)n Remember: Example: The simplest whole number ratio of atoms of each element in the compound. The actual number of atoms of each element that are present in a molecule of the compound Compound – Ethene Molecular formula - C2 H 4 Compound – Glucose Molecular formula - C6 H12O 6 Empirical formula - CH 2 Empirical formula - CH 2O 2. To find the empirical formula of a compound Example of calculation: a) When 11.95 g of metal X oxide is reduced by hydrogen, 10.35 g of metal X is produced. Find the empirical formula of metal X oxide [ RAM; X,207; O,16 ] Element X O Mass of element(g) 10.35 11.95-10.35 Number of moles of atoms 10.35÷207 (11.95-10.35)÷16 Ratio of moles Simplest ratio of moles Empirical formula : …………… 15 16 b) A certain compound contains the following composition: Na 15.23%, Br 52.98% , O 31.79%, [ RAM : O, 16; Na, 23; Br,80] (Assume that 100g of substance is used) Element Na Br O Mass of element(g) 15.23 52.98 31.79 Number of moles of atoms 15.23 ÷23 52.98÷80 31.79÷16 Ratio of moles Simplest ratio of moles Empirical formula: Compound Molecular Formula Water H2O Carbon Dioxide CO2 Sulphuric Acid H2SO4 Ethane C2H4 Benzene C6H6 Glucose C6H12O6 Empirical formula Value of n CO2 CH2 a) 2.58g of a hydrocarbon contains 2.16 g of carbon. The relative molecular mass of the hydrocarbon is 86. [RAM H,1; C,12] i. ii. Find the empirical formula of the hydrocarbon Find the molecular formula of the carbon. 16 17 3. Chemical Formula for ionic compounds: *Memorise… The formulae of some common cations and anions : Cation Formula Anion Formula Hydrogen ion H Flouride ion F Lithium ion Li Chloride ion Cl Sodium ion Na Bromide ion Br Potassium ion K Iodide ion I Magnesium ion Mg 2 Hydroxide ion OH Calcium ion Ca 2 Nitrate ion NO3 Barium ion Ba 2 MnO4 Copper(II) ion Cu 2 Manganate(VII) ion Ethanoate ion CH 3COO Iron(II) ion Fe 2 Oxide ion O 2 Iron (III) ion Fe3 Sulphate ion SO4 Lead (II) ion Pb 2 Sulphide ion S 2 Zinc ion Zn 2 Carbonate ion CO3 Chromium (III) ion Cr 3 Cr2O7 Aluminium ion Al 3 Dichromate (VI) ion Phosphate ion Ammonium ion NH 4 Silver ion Ag 17 PO4 2 2 3 18 a) Chemical formula of an ionic compound comprising of the ions Xm+ and Yn- is constructed by exchanging the charges of each element. The formula obtained will XnYm example : Sodium oxide Na+ +1 Copper (II) nitrate O2-2 2 1 Cu2+ 2+ NO3-1 1 2 = Na2O = Cu(NO3)2 Construct a chemical formula for each of the following ionic compounds: (a). Magnesium chloride sulphate (b). Potassium carbonate (c). Calcium (d). Copper (II) oxide (e). Silver nitrate (f). Zinc nitrate (g). Aluminium oxide (h). Iron(II) hydroxide (i). Lead(II) sulphide 3.6 CHEMICAL EQUATIONS Example: C (s) + O2 (g) CO2 (g) Reactant product *Qualitative aspect of chemical equation: 1. 2. 3. 4. Arrow in the equation the way the reaction is occurring Substances on the left-hand side reactants. Substances on the reight-hand side products. State of each substance solid : (s), liquid (l), gas (g) and aqueous reaction (aq) Example: 2 H 2 (g) + O2 (g) 18 2 H 2O (l) 19 2 molecules Or 2 mol 1 molecule or 1 mol 2 molecules or 2 mol * Quantitative aspect of chemical equations 1. Coefficients in a balanced equation the exact proportions of reactants and products in a equation. Write a balanced equation for each of the following reactions and interpret the equations quantitatively. (a). Carbon monoxide gas + oxygen gas carbon dioxide gas ______________________________________________________________________ Interpreting: ___________________________________________________________________ (b). Hydrogen gas + nitrogen gas ammonia gas ______________________________________________________________________ Interpreting: ___________________________________________________________________ (c). Aluminium + Iron (III) oxide aluminium oxide + Iron ______________________________________________________________________ Interpreting: ___________________________________________________________________ ** Numerical Problems Involving Chemical Equations Hydrogen peroxide decomposes accordin to the following equation: 2 H 2O2 (l) 2 H 2O (l) + O2 (g) 1. Calculate the volume of oxygen gas, O2 measured at STP that can be obtained from the decomposition of 34 g of hydrogen peroxide, H 2O2 . [Relative atomic mass : H, 1 ; O, 16. Molar volume : 22.4 dm 3 mol 1 at STP] (Ans: 11.2 dm3) 2.Silver carbonate Ag2CO3 breaks down easily when heated to produce silver metal 2 Ag2CO3(l) 4 Ag (s) + 2 CO2 (g) + O2 Find the mass of silver carbonate that is required to produce 10 g of silver [Relative atomic mass: C, 12 ; O, 16 ; Ag, 108] 19 20 (Ans : 12.77g) 3. 16 g of copper (II) oxide, CuO is reacted with excess methane, CH 4 . Using the equation below, find the mass of copper that is produced. [Relative atomic mass : Cu, 64 ; O, 16] 4 CuO (s) + CH 4 (g) 4 Cu (s) + CO2 (g) + 2 H 2O (l) (Ans : 16 g) 4.A student heats 20 g of calcium carbonate CaCO3 strongly. It decomposes according to the equation below: CaCO3 (s) CaO (s) + CO2 (g). (a). If the carbon dioxide produced is collected at room conditions, what is its volume? (b). Calculate the mass of calcium oxide, CaO produced. [Relative atomic mass: C, 12 ; O, 16; Ca, 40. Molar volume : 24 dm3 mol 1 at room conditions] (Ans : (a). 4.8 dm 20 3 (b) 11.2 g) 21 CHAPTER 4 : PERIODIC TABLE of ELEMENTS 4.1 THE PERIODIC TABLE OF ELEMENTS Historical Development of the Periodic Table Arrangement of elements in the Periodic Table a) Elements are arranged in an increasing order of proton number b) Vertical columns are called group ( Group 1 18) c) Horizontal rows are called period ( Period 1 7) d) Elements with similar chemical properties are placed in the same group e) The group number of the elements with 1 to 2 valence electrons = the number of valence electrons in its atom. f) The group number of the elements with 3 to 8 valence electrons = the number of valence electrons in its atom + 10 g) The period number of an element = the number of shells occupied with electrons in its atom. 1. Complete the table below Element Electron arrangement Number of valence electrons Group Number of shells occupied Period Element 1 1 H 4 2 He 7 3 Li 9 4 11 5 Be B 2.1 12 6 C 14 7 N 16 8 O 2.4 19 9 F 20 10 Ne 2.7 2 8 14 17 2 2 23 11 Na Electron 2.8.1 arrangement Number of valence electrons Group 1 Number of shells occupied Period 24 12 Mg 27 13 Al 28 14 31 15 Si P 32 16 S 35.5 17 Cl 40 18 Ar 39 19 K 40 20 Ca 6 16 3 2 4 2.An atom of element E has 10 neutrons. The nucleon number of element E is 19. In which group and period is element E located in the Periodic Table? 3. An atom of element G has 3 shells occupied with electrons. It is placed in group 21 22 17 of the Periodic Table. What is the electron arrangement of atom G? 4.2 Group 18 Element known as noble gases: Helium, neon, argon, krypton, xenon & radon monoatomic all noble gases are inert – chemicallt unreactive ** The electron arrangement of noble gases are very stable because the outermost occupied shells are full Uses of Group 18 elements: 1. Helium gas – to fill airships and weather balloons 2. Neon gas – used in advertising lights and television tubes 3. Argon gas – to fill light bulbs 4. Krypton gas – used in lasers to repair the retina of the eye 5. Radon gas – treatment of cancer 6. Xenon gas – used for making electron tubes and stroboscopic lamps 4.3 Group 1 Elements (Alkali Metals) Lithium, sodium, potassium, rubidium, caesium & francium uses of Group 1 elements: a) Lithium – batteries in calculator, watches and cameras b) Sodium - Na2 CO3 in soda-lime glass c) Potassium - KNO3 as fertiliser. * physical properties: softmetals, low densities, low melting & boiling points, silvery and shiny surfaces, good conductors of heat and electricity *Chemical Properties of Group 1 Elements 1. react vigorously with water to produce alkaline metal hyrdroxide solutions and hydrogen gas Example: 2Li + 2H 2 O 2LiOH + H 2 Write down the balanced equation when potassium reacts with water _______________________________________________________________ 2. react (burn) in oxygen gas rapidly to produce white solid metal oxides Example: 4Li + O2 2Li2 O Write down the balanced equation when rubidium reacts with oxygen _______________________________________________________________ 3. burn in chlorine gas Cl2 , to form white solid metal chlorides. Example: 2Na + Cl2 2NaCl Write down the balanced equation when potassium reacts with chlorine gas _______________________________________________________________ ** The reactivity of Group 1 elements increases when going down the group. Explain why. 22 23 _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ** Potassium reacts more vigorously with water as compared to sodium. Explain. (Proton number: Na, 11 ; K, 19) _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ (refer text book pg 67&68) To Investigate The Chemical Properties of Lithium, Sodium & Potassium (A) The Reaction of alkali metals With Water, H 2 O Problem Statement: How does the reactivity of Group 1 elements change when they react with water? Hypothesis: When going down Group 1, alkali metals become more reactive in their reactions with water. Variables: Manipulated variable – Different types of alkali metals Responding variable – Reactivity of metals Fixed variables – water, size of metals Procedure: (refer to practical book pg 39) Data & Observation (complete this table!) Alkali metal Lithium Sodium Potassium (B) Observation The Reaction of alkali metals With Oxygen, O2 (This procedure also can be used to test the reaction of alkali metals with chlorine gas!) Problem Statement: _________________________________________________ _________________________________________________ Hypothesis: ___________________________________________________ ___________________________________________________ Variables: Manipulated variable – ________________________________ Responding variable – ________________________________ Fixed variables – ____________________________________ Procedure; (refer practical book pg 36) Data & Observation (This reaction of alkali metals with chlorine gas will give the same observations!) 23 24 Alkali metal Lithium Sodium Potassium Observation Based on your results, arrange the alkali metals in ascending order of reactivity. _______________________________________________________________ Write the chemical equations for the reactions between the products from the combustion of each alkali metal with water.(refer text book pg 67) 1. ____________________________________________________________ 2. ____________________________________________________________ 3. ____________________________________________________________ 4.4 Group 17 Elements (Halogens) Fluorine, chlorine, bromine, iodine and astatine uses of Group 17 elements: 1) Chlorine – water treatment, bleaching agent 2) Bromine – weaker bleaching agent 3) Iodine – needed in human thyroid gland to produce hormones *Physical properties: Low melting and boiling points. Fluorine: pale yellow gas Chlorine: greenish-yellow gas Bromine: reddish-brown gas Iodine: purplish-black gas *Remember melting and Cl2 Br2 I2 colour of Density boiling points halogens increases increase becomes darker When going down the Group 17, the melting and boiling points increase. Explain __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ (refer text book pg 70) ** Chemical Properties of Group 17 Elements 1. react with water to form two acids Example: Cl2 + H 2 O + HCl hydrochloric acid HOCl hypochlorus acid Write a balanced equation when bromine reacts with water. __________________________________________________________________ 2. in gaseous state react with hot iron to form a brown solid, iron (III) halides. Example: 2 Fe + 3Br2 2FeBr3 24 25 Write a balanced equation when iodine vapour reacts with iron __________________________________________________________________ 3. react with sodium hydroxide solution, NaOH , to form sodium halide, sodium halite (I) and water Example: I 2 + 2NaOH NaI + NaOH + H 2 O Write a balanced equation when chlorine reacts with sodium hydroxide solution __________________________________________________________________ The reactivity of Group 17 elements decreases when going down the group. Explain why. ___________________________________________________________________ ___________________________________________________________________ ________________________________________________________________ Chlorine gas reacts more vigorously with hot iron as compared to bromine gas. Explain (Proton number: Cl, 17 ; Br, 35) ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ _______________________________________________________________ (refer text book pg 71) To investigate the Chemical properties of Group 17 elements. The Reaction of halogens with iron (refer practical book pg 44) Data and Observation (Complete this form) Halogens Observation Chlorine Bromine Iodine Based on your results, arrange the halogens, Cl2 , Br2 , I 2 in ascending order of reactivity. __________________________________________________________________ Element E is placed below element D in Group 17 of the Periodic Table. (a). Compare the melting and boiling points of element D with element E. Explain your answer 25 26 _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ (b). Write an equation for the reaction between element D and hot iron _______________________________________________________________ 4.5 Elements In A Period (refer text book pg 73) Example: Period 3 in the Periodic Table – Properties of Elements Element Proton number Electron arrangement Atomic radius (pm) Physical state at room temperature Electronegativity * Na 11 Mg 12 Al 13 Si 14 P 15 S 16 Cl 17 Ar 18 186 160 143 118 110 104 100 94 Solid Solid Solid Solid Solid Solid Gas Gas 0.9 1.2 1.5 1.8 2.1 2.5 3.0 - Across Period 3: (refer text book pg 73) 1. The proton number ________________ by one unit from one element to the next element 2. All the atoms of elements have _______________ shells occupied with electrons. 3. The number of valence electrons in each atom _______________ from 1 to 8. 4. The physical state at room temperature changes from __________ to ___________ 5. The atomic radius (atomic size) of elements ________________. _________________________________________________________ _________________________________________________________ 6. The electronegativity of elements. _______________________ _________________________________________________________ _________________________________________________________ 7. The oxides of elements change from basic to acidic properties. Example: Na2 O , MgO , Al 2 O3 , SiO2 P4 O10 SO2 Cl 2 O7 Below are some oxides of elements of Period 3. *Sodium oxide, Na2 O *Aluminium oxide, Al 2 O3 *Silicon (IV) oxide, SiO 2 *Sulphur dioxide, SO2 26 27 (a). Which of these oxides can react with (i) dilute nitric acid, HNO3 ?________________________________________ (ii) sodium hydroxide, NaOH solution?_______________________________ (b). Based on your answers in (a), what inferences can you make about the properties of each of the oxides? _______________________________________________________________ 7 3 Q2 Li , 12 6 C , 199 F The above show the symbols of lithium, carbon and fluorine. (a). Which period in the Periodic Table can you find the three elements? Explain. _______________________________________________________________ (b). Arrange the three elements in order of increasing atomic size. _______________________________________________________________ (c). Compare the electronegativity of the three elements. Explain your answer. _______________________________________________________________ _______________________________________________________________ 4.6 Transition Elements elements from Group 3 to Group 12 in the Periodic Table all are metals high melting and boiling points ; high densities good conductors of heat and electricity. exhibit three special characteristics: 1. transition elements show different oxidation numbers in their compounds. Example: Iron: Copper: 2 oxidation numbers +2, +3 2 oxidation numbers 27 28 2. transition elements form coloured ions or compounds. Example: Cu 2+ - blue Fe2+ - green MnO4- - purple CrO42- - yellow Fe3+ - brown 3. transition elements and their compounds are useful catalysts. Example: (refer text book 77) 1. Haber process – Manufacture of ___________ Catalyst: iron 2. Ostwald process – manufacture of ______________ Catalyst: __________ 3. Manufacture of margarine Catalyst: _____________ 4. Contact process – manufacture of ______________ Catalyst: ___________________ ****(Zinc is usually not classified as a transition element because it does not exhibit the special characteristic of transition elements!) ****(Precious stones such as emerald, rubies, sapphire and jade are beautiful due to the colours of the transition element compounds present in them!) 28 29 1 Diagram 1.1 shows the atomic structure of elements X and Y. (Rajah 1.1 menunjukkan struktur atom bagi unsur X dan Y.) DIAGRAM 1.1 (a) What is the proton number of element X? (Apakah nombor proton bagi unsur X?) ………………………………………………………….…………………….………………… [1 mark] (b) (i) Atom of element X has isotopes. What is meant by isotopes? (Atom unsur X mempunyai isotop. Apakah yang dimaksudkan dengan isotop?) …………………………………………………………………….……………………… [1 mark] (ii) State one example of an isotope. (Nyatakan satu contoh isotop.) …………………………………………………………………………………………… [1 mark] (c) (i) Atom of element Y has a nucleon number of 23. Calculate the number of neutrons in atom Y. (Atom unsur Y mempunyai nombor nukleon 23. Hitungkan bilangan neutron bagi atom Y.) …………………………………………………………………………………………… [1 mark] (ii) Write the standard representation of atom Y. (Tuliskan simbol atom unsur Y.) …………………………………………………………………………………………… [1 mark] (d) Ethanol is an organic compound. Its melting point is –117 oC and its boiling point is 78 oC . (Etanol ialah satu sebatian organik dengan takat lebur – 117 oC dan takat didih 78 o C.) (i) What is the physical state of ethanol at room temperature? (Apakah keadaan fizik etanol pada suhu bilik?) ……………………………………………………………………………..…………… [1 mark] 29 30 (ii) Draw the arrangement of particles of ethanol at 100 oC. (Lukiskan susunan zarah etanol pada 100 oC.) 100 oC [1 mark] (iii) State how the movement of ethanol particles changes when heated from room temperature to 100 oC. (Nyatakan bagaimana pergerakan zarah-zarah etanol berubah apabila dipanaskan dari suhu bilik ke 100 oC.) …………………………………………….………………………………..…………… [1 mark] (iv) Sketch the graph of temperature against time when ethanol is heated from room temperature to 100 oC. (Lakarkan graf suhu melawan masa apabila etanol dipanaskan daripada suhu bilik ke 100 oC) Temperature/oC Time/min 2 Figure 2.1 shows the chemical symbols which represent elements R, S and T. (Rajah 2.1 menunjukkan simbol kimia yang mewakili unsur-unsur R, S dan T.) 35 12 39 17 6 19 30 [2 marks] 31 R (a) (i) S T FIGURE 2.1 Write the electron arrangement of atom T. (Tuliskan susunan elektron bagi atom T.) ………………………………………………………………………………...… [1 mark] (ii) State the period and the group for element T in the Periodic Table. (Nyatakan kala dan kumpulan bagi unsur T dalam Jadual Berkala.) Period (Kala) : ….…………………………………………………………….. Group (Kumpulan) ………………………………………………….………... [2 marks] (b) Atoms of R and S can react to form a compound. (Atom R dan atom S boleh bertindak balas untuk membentuk satu sebatian.) (i) Name the type of bond in the compound formed between atoms R and S. (Nyatakan jenis ikatan dalam sebatian yang terbentuk antara atom R dan atom S.) ……………………………………………………………………………. [1 mark] (ii) Give one physical property of the compound in (b)(i). (Beri satu sifat fizik bagi sebatian di (b)(i).) ….…………………………………………………………………………… [1 mark] (c) Atoms of R and T can also react to form a compound. Draw the electron arrangement for the compound formed. (Atom R dan atom T juga boleh bertindak balas untuk membentuk satu sebatian. Lukiskan susunan elektron bagi sebatian yang terbentuk.) (d))) Iron, copper, nickel and chromium are examples of transition elements. (Ferum, kuprum, nikel dan kromium adalah contoh unsur peralihan.) [ 2 marks] 31 32 (i) State the position of transition elements in the Periodic Table. (Nyatakan kedudukan unsur peralihan dalam Jadual Berkala.) ……………………………………………………………….…….…………… [1 mark] (ii) State two special characteristics of transition elements. (Nyatakan dua ciri istimewa bagi unsur peralihan.) ………………………………………………………………….……………… [2 marks] 3 Diagram 2 shows part of the Periodic Table of the Elements. U, V, W, X, Y and Z do not represent the actual symbol of the elements. U W V X Y Z DIAGRAM 2 (a) Using the letters in the Periodic Table of the Elements in Diagram 2, answer the following questions. (i) Choose two elements in period 3 …………………………………………………………………………………………… [1 mark] (ii) Which element will form coloured compound? …………………………………………………………………………………………… [1 mark] (iii) Write the electron arrangement for an atom of element V. …………………………………………………………………………………………… [1 mark] (iv) Which element is chemically unreactive ? …………………………………………………………………………………………… [1 mark] (v) Explain your answer in (a)(iv) …………………………………………………………………………………………… …………………………………………………………………………………………… 32 33 [2 marks] (vi) State one of the uses of U. …………………………………………………………………………………………… [1 mark] (b) When X reacts with cold water, hydroxide solution is formed and a gas is released. (i) Name the gas ………………………………………….………………………………………………………… [ 1 mark ] (ii) Write the chemical equation for the reaction ……………………………………………………………………………………… [ 2 marks ] 33