Worked+Solutions+for+Area+of+Study+1


 * There are some things that didn't copy across, OBVIOUSLY you will be able fill in the gaps.**

Unit 1 Area of Study 1 Review Multiple-choice questions Q1. Which of these proposals corresponds to the ideas put forward by John Dalton in 1804? I Matter consists of indivisible particles. II Atoms of a particular element can vary in their mass. III The proportion and type of atom is always the same in a particular compound. A1. C. Dalton did not say that atoms of a particular element could vary in their mass. He had no concept of the existence of isotopes. Q2. When he first constructed his periodic table, Mendeleev arranged the known elements: A2. D. Atomic number; electronic configuration and mass number were not known at that time. Q3. Ernest Rutherford contributed to knowledge about the structure of the atom by: A3. B. This was part of the research that Rutherford and his team of co-workers did that showed that most of the mass, and the positive charge, of an atom is concentrated in the nucleus. Q4. Which of the following elements would have atoms with the largest atomic radius? A4. B. Sodium is on the left-hand side of period 3; hence, its outer-shell electron is subject to the lowest core charge for that period. Q5. Which of the following elements would be expected to show greatest similarity in chemical properties to the element that has 14 electrons in its neutral atoms? A5. D. Ge is in the same group of the periodic table, with four outer-shell electrons. Q6. The Pauli exclusion principle states that: A6. D Q7. A double negatively charged ion has eight protons. The number of electrons in the ion is: A7. A. The double negative charge means there are two more electrons than protons, giving ten electrons in the ion.
 * A** I only
 * B** I and II
 * C** I and III
 * D** I, II and III
 * A** in order of their atomic number
 * B** according to their electronic configuration
 * C** into vertical groups according to their mass number
 * D** into horizontal periods according to their atomic mass
 * A** discovering the composition of alpha particles
 * B** discovering that protons are found in the nucleus of an atom
 * C** proving the existence of neutrons in the nucleus of an atom
 * D** proposing that electrons move in circular orbits around the nucleus
 * A** Li
 * B** Na
 * C** F
 * D** Cl
 * A** Al
 * B** P
 * C** Ga
 * D** Ge
 * A** all atomic orbitals must hold two electrons
 * B** an atomic orbital must hold a minimum of two electrons
 * C** a new subshell is started whenever an atomic orbital holds two electrons
 * D** an atomic orbital may hold a maximum of two electrons
 * A** 10
 * B** 8
 * C** 6
 * D** 2

Q8. A sample of chlorine was thought to consist of the isotopes Cl and  Cl. If the relative atomic mass of this sample of chlorine was found to be 35.5, it can be said that: A8. B. There is a greater abundance of than , as the relative atomic mass is closer to 35 than to 37. Q9. The number of neutrons in K+ is: A9. C. The number of neutrons is the mass number (39) minus the atomic number (19). Q10. Which one of the following has a //different// electronic configuration from the others? A10. B. All have ten electrons except K+, which has eighteen electrons. Q11. In which groups of the periodic table would you //not// expect to find a metal? A groups 14 and 15 B groups 14 and 18 C groups 13 and 17 D groups 17 and 18 A11. D. These groups have a large number of electrons in the outer shell and cannot lose electrons easily.
 * A** there are equal amounts of [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image002.gif width="17" height="28"]] Cl and [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image004.gif width="17" height="28"]] Cl
 * B** there is a greater abundance of [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image002.gif width="17" height="28"]] Cl than [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image004.gif width="17" height="28"]] Cl
 * C** there is a greater abundance of [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image004.gif width="17" height="28"]] Cl than [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image002.gif width="17" height="28"]] Cl
 * D** the sample consists of a different isotope with a relative isotopic mass of 35.5
 * A** 18
 * B** 19
 * C** 20
 * D** 39
 * A** Na+
 * B** K+
 * C** Ne
 * D** F–

Q12. Which one of the following pairs of elements is most likely to combine to form a compound with properties similar to those of sodium chloride? A calcium and bromine B carbon and oxygen C copper and nickel D phosphorus and chlorine A12. A. Calcium is a metal with a small number of electrons in the outer shell. Bromine is a non-metal with a large number of electrons in the outer shell. Sodium chloride is also a compound of a metal and a non-metal, so it will have similar properties to a compound of calcium and bromine. Q13. Isotopes of an element contain: A the same atomic number and the same mass number B the same atomic number and a different mass number C a different atomic number and the same mass number D a different atomic number and a different mass number A13. B. Isotopes have the same number of protons (atomic number) and a different number of neutrons (mass number is protons plus neutrons). Q14. Going down group 7 of the periodic table, the electronegativity: A decreases because the atomic radius increases B increases because the atomic number increases C decreases because the atomic number increases D increases because the number of subshells increases A14. A. The atomic radius increases; hence, the attraction for an additional electron decreases. Q15. The relative atomic mass of magnesium, //A//r(Mg), is 24.31. The most important reason why it is not a whole number is that: A magnesium atoms lose electrons when they react B the relative atomic mass given is only an approximation C not all atoms of magnesium have the same number of neutrons D the mass of the magnesium atom is compared to the mass of the 12C isotope A15. C. Relative atomic mass is an average of the relative isotopic masses for an element. Isotopes are atoms of magnesium with different numbers of neutrons.

Q16. Which of the following lists contain empirical formulas only? A C2H2, CBr4, Ca(OH)2, KMnO4 B NH3, N2H4, C6H5CH3, HCOOH C H2SO4, Al2(SO4)3, C6H5CH3, CH3Cl D HCOOH, C2H6O, Fe2O3.//x//H2O, C6H12O6 A16. C. The following are not empirical formulas: H2SO4, Al2(SO4)3, C6H5CH3, CH3Cl. A compound has an empirical formula of CH. A 0.25 mol sample of the compound weighs 13 g. The molecular formula is: A C8H8 B C6H6 C C4H4 D C2H2 A17. C. Molar mass of hydrocarbon is = 52 g mol–1 Molar mass of CH unit is 13 g mol–1. Number of units = = 4 \ molecular formula is C4H4 Short-answer questions Q18. a In what part of the periodic table are the metals found? Why are they found there? b The helium atom contains two electrons in the outer shell. Why is helium not placed in group 2 with the other elements also containing two electrons in the outer shell? c The heavier elements, atomic numbers 87–112, are all metals. Explain this fact. d Some metallic elements are very reactive. Which group of the periodic table contains the most reactive metals? A18.
 * Q17.**
 * a** Metals are found at the left and bottom of the periodic table. These elements have a small number of electrons in their outer shell.
 * b** Helium has a full outer shell and cannot easily donate these electrons as metals do.
 * c** Elements 87–112 all have just one or two outer-shell electrons, which can be easily lost.
 * d** group 1

Q19. a Explain, using suitable examples, the relationship between the electronic configuration of an element and its position in the periodic table. b Consider the following: Na, Cl, Mn, Ca2+, O2–, Al3+. For each: i give its electronic configuration ii indicate its position in the periodic table (e.g. group 17, period 2, or transition series, period 4) A19. The number of electrons in the outermost shell of an element determines the group number of the element. For example, calcium has two electrons in its outermost shell and so belongs to group 2. Transition metals are those that have a ‘d’ subshell being filled. Lanthanides and actinides have ‘f’ subshells being filled. Cl 1s22s22p63s23p5 group 17 period 3 Mn 1s22s22p63s23p63d54s2 transition series period 4 Ca2+ 1s22s22p63s23p6 group 2 period 4 O2– 1s22s22p6 group 16 period 2 Al3+ 1s22s22p6 group 13 period 3 Q20. Select your answers to the questions below from the following list of elements: Cl, C, Na, Mg, K, O, F, Al, N, Ca. Which elements: a are in period 2 of the periodic table? b are in period 3 of the periodic table? c are in group 1 of the periodic table? d are in group 2 of the periodic table? e are in group 13 of the periodic table? f are in group 16 of the periodic table? g are classified as metals? h have one valence electron? i have three valence electrons? j has the highest molar mass? A20. Q21. a Supply the missing information in the table. b The neutron was not discovered until more than 30 years after the discovery of the proton and the electron. Why was the neutron more difficult to detect? A21. Q22. i relative atomic mass ii relative molecular mass iii mole iv Avogadro’s number v molar mass b Write the electronic configuration for the element phosphorus. c When 0.100 g of white phosphorus is burned in oxygen, 0.228 g of an oxide of phosphorus is produced. The molar mass of the oxide is 284 g mol–1. i Determine the empirical formula of the phosphorus oxide. ii Determine the molecular formula of the phosphorus oxide. d Would you expect the properties of the oxide of phosphorus to be more similar to those of sodium chloride or those of water? Explain your answer.
 * a** For any element, the shell of the highest order of an element containing electrons determines the period of an element. For example, in calcium the fourth shell contains electrons and, being the highest order in which electrons are found, makes calcium a period 4 element.
 * b** Na 1s22s22p63s1 group 1 period 3
 * a** C, N, O and F
 * b** Na, Mg, Al and Cl
 * c** Na and K
 * d** Mg and Ca
 * e** Al
 * f** O
 * g** Na, Mg, Al, K and Ca
 * h** Na and K
 * i** Al
 * j** Ca
 * Atomic number || Neutron number || Mass number || Symbol ||
 * 4 || **(i)** || 9 || [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image017.gif width="11" height="24"]] Be ||
 * 8 || **(ii)** || **(iii)** || [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image019.gif width="15" height="25"]] O ||
 * **(iv)** || **(v)** || **(vi)** || [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image021.gif width="15" height="25"]] P ||
 * 34 || **(vii)** || 78 || **(viii)** ||
 * a i** 5
 * ii** 9
 * iii** 17
 * iv** 15
 * v** 16
 * vi** 31
 * vii** 44
 * viii** [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image023.gif width="32" height="25"]]
 * b** Most of the instruments used for investigating the struc­ture of the atom are based on the use or measure­ment of electric charge. As the neutron is an uncharged part­icle, it was not detected by these instruments.
 * a** Explain the meanings of the following terms:

A22. P : O 0.100 g : (0.228 – 0.100) g 0.100 g : 0.128 g Step 2: Calculate the ratio by amount (in moles). : 0.003 229 mol : 0.008 mol Step 3: Divide by the smaller amount. : 0.4036 : 1 Step 4: Express as integers by multiplying by 5. 2 : 5 \ empirical formula of the compound is P2O5 The molar mass of one of these units is ((2 ´ 30.974) + (5 ´ 16)) = 141.948 g mol–1. The number of units in a molecule = molar mass of the compound/molar mass of one unit = = 2 \ molecular formula of the compound is P4O10
 * a i** Relative atomic mass—the weighted mean of the relative masses of the isotopes of an element on the 12C scale.
 * ii** Relative molecular mass—the relative mass of a molecule on the 12C scale.
 * iii** Mole—the amount of substance that contains the same number of specified particles as there are atoms in exactly 12 g of 12C.
 * iv** Avogadro’s number—the number of carbon atoms in exactly 12 g of 12C (approximately 6.02 ´ 1023).
 * v** Molar mass—mass in grams of a mole of a substance.
 * b** 1s22s22p63s23p3
 * c i** Step 1: Write the ratio by mass.
 * ii** As the empirical formula is P2O5, the molecule must contain a whole number of P2O5 units.
 * d** Properties are more similar to those of water. Water is a compound of two non-metals (hydrogen and oxygen), as is the oxide of phosphorus, since both phosphorus and oxygen are non-metals.

Q23. The original version of the periodic table was devised by the Russian chemist Dmitri Mendeleev in 1869. In the modern form of the periodic table, the elements are arranged in order of atomic number. A23. · in order of increasing atomic mass; · with elements having similar chemical properties in vertical groups. Q24. The electronic configurations of seven elements (A–G) are given below. A 1s22s22p5 B 1s22s22p63s1 C 1s22s22p63s13p5 D 1s22s22p63s23p64s2 E 1s22s22p63s23p63d64s1 F 1s22s22p63s23p63d84s2 G 1s22s22p63s23p63d104s24p5 Indicate which one or more are likely to be: A24.
 * a** What were the //two// pieces of information that he used to devise the table?
 * b** What information about the structure of the atom is given by its atomic number?
 * c** What is the link between the atomic number of an element and the block in the periodic table in which it would be found?
 * d** Consider the element with atomic number 14.
 * i** Write the full electronic configuration.
 * ii** In which group, period and block of the periodic table would it be found?
 * a** He arranged the known elements:
 * b** the number of protons
 * c** For a neutral atom, the number of protons equals the number of electrons, and the electrons are arranged into shells and subshells of increasing energy. The block of the periodic table corresponds to the highest energy subshell of electrons in the particular atom.
 * d i** 1s22s22p63s23p2
 * ii** group 4, period 3, p-block
 * a** metals
 * b** d-block elements
 * c** group 17 elements
 * d** period 3 elements
 * e** elements not in the ground state
 * a** B, D, E, F
 * b** E, F
 * c** A, G
 * d** B, C
 * e** C, E

Q25. A25. Q26. Give explanations for the following: A26.
 * a** Give the ground-state electronic configuration of calcium (Ca).
 * b** Explain, giving an example of the new electronic configuration, what happens to the energy levels of the electrons when the atom in the ground state is provided with sufficient energy to become:
 * i** an excited atom
 * ii** a charged ion
 * c** The stable ion of calcium is Ca2+. What would be the difference in atomic radius of a Ca atom and a Ca2+ ion?
 * d** Why would a Ca atom and a Ca2+ ion have almost the same mass?
 * e** Give the symbol of two elements that would have chemical properties similar to those of calcium.
 * a** 1s22s22p63s23p64s2
 * b i** Electrons are promoted to a higher energy level. An example of an electronic configuration of an excited calcium atom could be (several answers possible): 1s22s22p63s23p64p2.
 * ii** With sufficient energy, a calcium atom can lose its valence electrons to form a cation e.g. Ca2+ with electronic configuration 1s22s22p63s23p6.
 * c** The ion is much smaller as electrons occupy most of the atom’s volume and the ion has one less electron shell than the atom.
 * d** The mass of electrons is negligible in comparison to that of the protons and neutrons in an atom. The number of protons and neutrons is the same in the atom and ion.
 * e** e.g. Mg, Sr
 * a** A sodium atom has a larger atomic radius than a chlorine atom, even though both belong to period 3.
 * b** A sodium ion (Na+) is much smaller than the sodium atom.
 * c** Fluorine is more electronegative than iodine.
 * a** Members of period 3 all have their outer-shell electrons in the third shell but the core charge increases across the period from +1 for sodium to +7 for chlorine. Hence, the outer-shell electrons in the chlorine are attracted more strongly to the nucleus, reducing the radius of the species.
 * b** From the electronic configuration for sodium, 1s22s22p63s1, it can be seen that the Na atom has three shells of electrons but the Na+ ion has lost the single outer-shell electron and the remaining eight electrons of the second shell are then attracted to a greater core charge.
 * c** The fluorine atom is smaller than that of iodine. Electrons are attracted to fluorine atoms more strongly than to those of iodine because they are closer to the positively charged nucleus in fluorine. So, fluorine is more electronegative.

Q27. The following is a list of atoms: A,  B,  C,  D,  E,  F,  G,  H,  I. A27. Q28. A sample of magnesium carbonate weighs 21.8 g. A28. //M// = 24.3 + 12 + 3 ´ 16 = 84.3 g mol–1 Step 2: Calculate the amount (mol) of MgCO3. //n// = = = 0.2586 mol Step 3: Give answers with correct number of significant figures. //n// = 0.259 mol No. atoms per molecule = 3 Step 2: Calculate amount (mol) of oxygen atoms. //n// = 3 ´ 0.259 = 0.776 mol
 * a** Which pairs of atoms are isotopes?
 * b** Which atoms have equal numbers of protons and neutrons in the nucleus?
 * c** Which is an isotope of sulfur?
 * d** Which has one more electron than a magnesium atom?
 * e** Which is a group 2 element?
 * f** How many different elements are shown?
 * a** D and F, G and H
 * b** B, C, D and I
 * c** C
 * d** A
 * e** B
 * f** 7
 * a** Calculate the amount (mol) of magnesium carbonate present.
 * b** Calculate the amount (mol) of oxygen atoms present.
 * c** Calculate the number of carbon atoms present.
 * d** Calculate the total number of atoms present.
 * e** Calculate the percentage, by mass, of magnesium in magnesium carbonate.
 * a** Step 1: Calculate the molar mass of MgCO3.
 * b** Step 1: Calculate number of oxygen atoms per molecule.

No. atoms per molecule = 1 Step 2: Calculate amount (mol) of carbon atoms. //n// = 1 ´ 0.259 = 0.259 mol Step 3: Calculate number of carbon atoms. No. atoms = 0.259 ´ 6.02 ´ 1023 = 1.56 ´ 1023 atoms No. atoms per molecule = 5 Step 2: Calculate amount (mol) of atoms. //n// = 5 ´ 0.259 = 1.30 mol Step 3: Calculate total number of atoms. No. atoms = 1.30 ´ 6.02 ´ 1023 = 7.80 ´ 1023 atoms
 * c** Step 1: Calculate number of carbon atoms per molecule.
 * d** Step 1: Calculate number of atoms per molecule.
 * e** % of Mg in MgCO3 [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image057.gif width="143" height="44"]]
 * = [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image059.gif width="83" height="41"]] **
 * =** 28.8%

Ethylene glycol is a compound often used as an antifreeze in cars in cold weather. Its molar mass is 62 g mol–1. It has a percentage composition of 38.7% carbon, 9.7% hydrogen and the rest oxygen. Determine:
 * Q29.**
 * a** the empirical formula of ethylene glycol
 * b** the molecular formula of ethylene glycol

A29. The molecular formula is always a whole-number multiple of the empirical formula. The empirical formula provides the simplest whole-number ratio of atoms in a compound. The amount of each atom is found by using //n// =, where //m// is the mass in grams and //M// is the molar mass in g mol–1. Use a periodic table to find the molar masses of C, H and O. = 3.225 mol || //n// = = 3.225 mol || //n// = = 9.7 mol || \ empirical formula is CH3O Molar mass of the compound (molecular formula) = 62 g mol–1 \ number of CH3O units in one molecule = = 2 \ molecular formula is C2H6O2 Q30. Methane (CH4) is the major component of natural gas. A30. It is useful to remember the formula //m// = //nM//, where //m// is the mass in grams, //n// the amount of substance in mol, and //M// the molar mass in g mol–1. Use a periodic table to find the molar masses. //M//(C) = 12 g mol–1 and //M//(CH4) = 16 g mol–1. Remember also that the number of particles in 1 mol is Avogadro’s number, //N//A = 6.02 ´ 1023. = 0.006 25 mol \ number of molecules = //nN//A = 0.006 25 ´ 6.02 ´ 1023 = 3.76 ´ 1021 molecules
 * a**
 * || C || O || H ||
 * Mass || 38.7 g || 100 – (38.7 + 9.7) = 51.6 g || 9.7 g ||
 * Molar mass || 12 g mol–1 || 16 g mol–1 || 1 g mol–1 ||
 * Amount, using //n// = [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image053.gif width="24" height="41"]] || //n// = [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image064.gif width="36" height="41"]]
 * Divide all by smallest amount || [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image070.gif width="43" height="41"]] = 1 || [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image070.gif width="43" height="41"]] = 1 || [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image072.gif width="43" height="41"]] = 3 ||
 * Round off to whole numbers || 1 || 1 || 3 ||
 * b** Molar mass of a CH3O unit (empirical formula) = 12 + 3 + 16 = 31 g mol–1
 * a** What is the mass of 0.50 mol methane?
 * b** How many molecules are there in 0.100 g methane?
 * c** How many atoms are there altogether in 0.10 g methane?
 * d** How many protons are there in 0.10 g methane?
 * e** What is the percentage by mass of carbon in methane?
 * f** What mass of carbon would be present in 34 g methane?
 * a** //m//(CH4) = 0.50 ´ 16 = 8.0 g
 * b** //n//(CH4) = [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image076.gif width="44" height="41"]]

So, total number of atoms in 3.76 ´ 1021 molecules = 5 ´ 3.76 ´ 1021 atoms = 1.88 ´ 1022 atoms So, total number of protons in 3.76 ´ 1021 molecules = 10 ´ 3.76 ´ 1021 protons = 3.76 ´ 1022 protons = 75% = 26 g Q31. Cobalt (Co) has an atomic number of 27. Cobalt reacts with oxygen to form a compound, cobalt oxide, formula CoO. Cobalt oxide contains 78.6% by mass of cobalt. A31. As the empirical formula is CoO, the ratio is 1 : 1 = : 1.34 \ //M//(Co) = = 58.7 g mol–1
 * c** There are 5 atoms in each molecule of methane (1 of C and 4 of O).
 * d** There are 10 protons in each molecule of methane (6 in each C and 1 in each of the 4 H atoms).
 * e** %(C) = [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image078.gif width="21" height="41"]] × 100
 * f** //m//(C in 34 g) = 75% of 34 = 34 ´ [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image080.gif width="29" height="41"]]
 * a** Give the ground state electronic configuration of cobalt.
 * b** To what section of the periodic table does cobalt belong?
 * c** Use the above information to calculate the relative atomic mass of cobalt.
 * a** 1s22s22p63s23p63d74s2
 * b** first transition metal series or d-block
 * c** The empirical formula provides the simplest whole-number ratio of atoms in a compound. The amount of each atom is found by using //n// = [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image061.gif width="31" height="47"]], where //m// is the mass in grams and //M// is the molar mass in g mol–1. Use a periodic table to find the molar mass of O.
 * || Co || O ||
 * Mass || 78.6 g || 21.4 g ||
 * Molar mass || ? g mol–1 || 16 g mol–1 ||
 * Amount, using //n// = [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image053.gif width="24" height="41"]] || //n// = [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image082.gif width="53" height="44"]] || //n// = [[image:file:///C:/Users/08832689/AppData/Local/Temp/msohtmlclip1/01/clip_image084.gif width="36" height="41"]] = 1.34 mol ||

Q32.
 * a** Calculate the relative atomic mass of silicon from the data given below.
 * Relative isotopic mass || Relative abundance (%) ||
 * 27.98 || 92.2 ||
 * 28.98 || 4.7 ||
 * 29.98 || 3.1 ||

of the periodic table does silicon belong? A32. //A//// r //(Si) = = =  =  = 28.1
 * b** To what:
 * i** group
 * ii** period
 * a** Substitute into the formula for relative atomic mass.
 * b i** 14
 * ii** 3

Q33. The successive ionisation energies for an element have been plotted in the diagram. A33. Q34. The graphs show trends in some of the properties of elements as you go from top to bottom down group 17 of the periodic table. Which graph best represents the trend for: A34.
 * a** How many shells of electrons exist for this atom?
 * b** Use this information to write the electronic configuration for this element in its ground state.
 * c** What is the likely charge on the stable cation of the element?
 * a** 3
 * b** 1s22s22p63s1
 * c** 1 +
 * a** electronegativities?
 * b** first ionisation energies?
 * c** number of outer-shell electrons?
 * d** atomic radii?
 * a** C. Electronegativity
 * b** C. First ionisation energy decreases as atomic radius increases down a group.
 * c** A. Number of outer-shell electrons is constant within a group.
 * d** B: Atomic radius increases down a group as //n//th number of electron shells increases.