Paddington Academy1AS LEVEL CHEMISTRY1.1.1 ATOMS1.2.1 ELECTRON STRUCTURE1.3.1 PERIODICITYASSESSED HOMEWORKAnswer all questionsMax 85 marksName..Mark../85....%Grade 1.The Group 7 element bromine was discovered by Balard in 1826. Bromine gets its name from the Greek bromos meaning stench.Bromine consists of a mixture of two isotopes, 79Br and 81Br.(i)What is meant by the term isotopes?..................................................................................................................................................................................................................................................[1](ii)Complete the table below to show the atomic structures of the bromine isotopes.protonsneutronselectrons79Br81Br[2](iii)Write the full electronic configuration of a bromine atom.1s2 .................................................................[1][Total 4 marks]2.Metal A can be identified from its relative atomic mass.Analysis of a fifty pence coin showed that two isotopes of metal A were present with the following percentage abundances.isotopeisotope 1isotope 2relative isotopic mass63.065.0% abundance77.222.8(i)Define the term relative atomic mass.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[3] (ii)Calculate the relative atomic mass of the sample of metal A.Give your answer to three significant figures.answer ...........................[2](iii)Use your answer to (iii) and the Data Sheet to suggest the identify of metal A..........................................................................................................................[1][Total 6 marks]3.The element titanium, Ti, atomic number 22, is a metal that is used in the aerospace industry for both airframes and engines.A sample of titanium for aircraft construction was analysed using a mass spectrometer and was found to contain three isotopes, 46Ti, 47Ti and 48Ti. The results of the analysis are shown in the table below.isotope46Ti47Ti48Tirelative isotopic mass46.0047.0048.00percentage composition8.99.881.3(a)(i)Explain the term isotopes.................................................................................................................................................................................................................................[1] (ii)Complete the table below for atoms of two of the titanium isotopes.isotopeprotonsneutronselectrons46Ti47Ti[2] (b)Using the information in the first table, calculate the relative atomic mass of this sample of titanium.Give your answer to three significant figures.[2][Total 5 marks]4.A sample of carbon was found to contain 95% of 12C and 5% of 13C.(i)The 13C isotope has a relative isotopic mass of 13.00.Define the term relative isotopic mass............................................................................................................................................................................................................................................................................................................................................................................[2] (ii)Calculate the relative atomic mass of this sample of carbon to three significant figures.Ar = ............................................[2][Total 4 marks]5.Magnesium exists naturally as a mixture of its isotopes, 24Mg, 25Mg and 26Mg.The isotopes in magnesium can be separated by mass spectrometry. The diagram below shows a mass spectrometer.(i)Complete the table below to show the composition of the 25Mg and 26Mg isotopes.protonsneutronselectrons25Mg26Mg[2] (ii)Complete the electronic configuration of an atom of 24Mg.1s2 ....................................................................................................................[1] (iii)Results from the mass spectrum of a sample of magnesium are shown below.isotope24Mg25Mg26Mgrelative isotopic mass24.0025.0026.00% abundance78.6010.1111.29Calculate the relative atomic mass of the sample of magnesium.Give your answer to two decimal places.answer ...............................[2][Total 5 marks]6.Relative atomic mass, Ar, can be used to compare the masses of atoms of different elements.(i)Explain what you understand by the term relative atomic mass............................................................................................................................................................................................................................................................................................................................................................................[3](ii)The antimony in a bullet was analysed by a forensic scientist to help solve a crime. The antimony was found to have the following percentage composition by mass: 121Sb, 57.21%; 123Sb, 42.79%.Calculate a value for the relative atomic mass of the antimony. Give your answer to 4 significant figures.Ar ...................................[2][Total 5 marks]7.Carbon is in the p-block of the Periodic Table. Naturally occurring carbon contains a mixture of two isotopes, 12C and 13C.Complete the table below for the atomic structure of the isotopes 12C and 13C.isotopeprotonsneutronselectrons12C13C[Total 2 marks]8.Antimony, Sb, is a metal used in alloys to make lead harder. Bullets contain about 1% of antimony for this reason.Antimony has two main isotopes.(i)What do you understand by the term isotopes?..................................................................................................................................................................................................................................................[1] (ii)Complete the table below to show the properties of particles that make up isotopes.protonneutronelectronrelative massrelative charge[2][Total 3 marks]9.The diagram below shows the variation in the first ionisation energies of elements across Period 2 of the Periodic Table.(i)Define the term first ionisation energy............................................................................................................................................................................................................................................................................................................................................................................[3] (ii)Explain why the first ionisation energies show a general increase acrossPeriod 2............................................................................................................................................................................................................................................................................................................................................................................[2](iii)Explain why the first ionisation energy of B is less than that of Be............................................................................................................................................................................................................................................................................................................................................................................[2][Total 7 marks]10.In their reactions, calcium and strontium each lose electrons to form ions with a 2+ charge. The first and second ionisation energies of calcium and strontium are shown below.1st ionisation energy/ kJ mol12nd ionisation energy/ kJ mol1calcium5901145strontium5501064(i)Write an equation, with state symbols, to represent the second ionisation energy of calcium..........................................................................................................................[2] (ii)Why are the second ionisation energies of calcium and strontium greater than their first ionisation energies?...........................................................................................................................................................................................................................................................................................................................................................................[1] (iii)Explain why the first and second ionisation energies of strontium are less than those of calcium.......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[3][Total 6 marks]11.Electrons are arranged in energy levels.(a)An orbital is a region in which an electron may be found.Draw diagrams to show the shape of an s orbital and of a p orbital.s orbitalp orbital[2] (b)Complete the table below to show how many electrons completely fill each of the following.number of electronsa d orbitala p sub-shellthe third shell (n = 3)[3](c)The energy diagram below is for the eight electrons in an oxygen atom. The diagram is incomplete as it only shows the two electrons in the 1s level.Complete the diagram for the oxygen atom by:(i)adding labels for the other sub-shell levels,[1](ii)adding arrows to show how the other electrons are arranged.[1][Total 7 marks]12.Successive ionisation energies provide evidence for the arrangement of electrons in atoms. The table below shows the eight successive ionisation energies of oxygen.ionisation number1st2nd3rd4th5th6th7th8thionisationenergy / kJ mol11 3143 3885 3017 46910 98913 32771 33784 080(i)Define the term first ionisation energy.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[3](ii)Write an equation, with state symbols, to represent the third ionisation energy of oxygen..........................................................................................................................[2](iii)Explain how the information in the table above provides evidence for two electron shells in oxygen.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[2][Total 7 marks]13.This question refers to the elements in the first four periods of the Periodic Table. Ionisation energies provide information about the model for the electron structure of elements.(i)Explain why first ionisation energies show a general increase across Period 3, NaAr................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[3](ii)Write an equation, including state symbols, to represent the third ionisation energy of sodium..........................................................................................................................[1](iii)Element X is in Period 3 of the Periodic Table, NaAr.The first six ionisation energies of an element X are shown below.ionisationnumber1st2nd3rd4th5th6thionisation energy/kJ mol1789157732324 5561609119 785Predict, with reasons, the identity of element X.........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[2][Total 6 marks] 14.In a mass spectrometer, gaseous atoms are ionised.Explain why less energy is needed to ionise gaseous atoms of rubidium than gaseous atoms of sodium...............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[Total 3 marks]15.Barium, Ba, was discovered by Davy in 1808. The element gets its name from the Greek barys meaning heavy.The table below compares some properties of barium with caesium.elementCsBagroup12atomic number5556atomic radius / pm531435(i)Why do caesium and barium have different atomic numbers?.........................................................................................................................[1] (ii)State the block in the Periodic Table in which caesium and barium are found..........................................................................................................................[1](iii)Explain why the atomic radius of barium is less than the atomic radius of caesium.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[3] (iv)Predict and explain whether a barium ion is larger, smaller or the same size as a barium atom.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[2][Total 7 marks] 16.The atomic radii of nitrogen and oxygen are shown below.elementnitrogenoxygenatomic radius/nm0.0750.073Explain why a nitrogen atom is larger than an oxygen atom...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[Total 4 marks] 17.State and explain the trend in first ionisation energies shown by the elements with the atomic numbers 2, 10 and 18.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................[Total 4 marks]