1 Which of the following gives the electronic configurations for a chromium atom and a chromium(ii) ion? A [Ar]3d 4 4s 2 [Ar]3d 4

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1 1 Which of the following gives the electronic configurations for a chromium atom and a chromium(ii) ion? r 2+ [r]3d 4 4s 2 [r]3d 4 [r]3d 5 4s 1 [r]3d 4 [r]3d 4 4s 2 [r]3d 2 4s 2 [r]3d 5 4s 1 [r]3d 3 4s 1 2 In which of the following ions does the metal have an oxidation number of +3? 2 MnO 4 VO 2+ [Fe(N) 6 ] 4 [r (H 2 O) 4 ] + 3 What is the electronic configuration of the stable scandium ion? [r] 3d 0 4s 2 [r] 3d 1 4s 1 [r] 3d 0 4s 1 [r] 3d 0 4s 0

2 4 The shapes of the complexes [rl 4 ] and [Pt(NH 3 ] are [rl 4 ] [Pt(NH 3 ] square planar square planar tetrahedral tetrahedral square planar tetrahedral tetrahedral square planar 5 In which of the following ions does the metal have an oxidation number of +2? 2 MnO 4 VO 2+ [Fe(N) 6 ] 4 [r (H 2 O) 4 ] +

3 6 The electronic configuration of iron is [r]3d 6 4s 2. What is the electronic configuration of the iron(ii) ion, Fe 2+? 3d 4s [r] [r] [r] [r] 7 hromium has the electronic configuration [r]3d 5 4s 1. Which of the following compounds is unlikely to exist? K 3 ro 4 ro 2 KrO 2 l KrO 4

4 8 The shapes of the complexes [rl 4 ] and [u ] are [rl 4 ] [u ] tetrahedral linear square planar linear tetrahedral V-shaped square planar V-shaped 9

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8 17 Four complex ions have the following formulae: u(edta Zn(H 2 O) 6 2+ Ni(NH 3 ) 6 2+ rl 4 2 (a) Which complex ion is most likely to be tetrahedral in shape? (1) (b) Which complex ion is most likely not to be coloured? (1) (c) Each of these complex ions may be formed by ligand exchange from an aqua complex. For which complex ion is the entropy change of this reaction most positive? (1) (Total for Question 3 marks)

9 18 Which of the following successive ionization energies (values in kj mol 1 ) could have come from a transition element? 19 Which of the following gives the electronic configuration for chromium and for the r 3+ ion? r r 3+ [r]3d 4 4s 2 [r]3d 3 4s 0 [r]3d 5 4s 1 [r]3d 2 4s 1 [r]3d 5 4s 1 [r]3d 3 4s 0 [r]3d 4 4s 2 [r]3d 1 4s 2 20 Which of the following gives the colours of solutions containing r 2 O 7 2, ro 4 2, hydrated r 3+ and hydrated r 2+, in this order? Yellow, orange, green, blue Orange, yellow, green, blue Orange, yellow, blue, green Orange, green, yellow, blue

10 21 The compound [Pt(NH 3 ] is tetrahedral with no isomers. square planar with no isomers. tetrahedral with two isomers. square planar with two isomers. 22 The hexaaquacopper(ii) ion, [u(h 2 O) 6 ] 2+, is blue because the water ligands split the p-orbital energies and p-p electron transitions emit blue light. split the d-orbital energies and d-d electron transitions absorb all but blue light. split the p-orbital energies and p-p electron transitions absorb all but blue light. split the d-orbital energies and d-d electron transitions emit blue light. 23 Vanadium is classified as a transition metal. This is because vanadium is a d-block element. has incompletely filled d orbitals. forms stable ions with incompletely filled d orbitals. forms stable ions in which it has different oxidation states.

11 24 opper(ii) sulfate solution is blue. This is because excited electrons emit light in the blue region of the spectrum as they drop back to the ground state. excited electrons emit light in the red region of the spectrum as they drop back to the ground state. electrons absorb light in the red region of the spectrum and the residual frequencies are observed. electrons absorb light in the blue region of the spectrum and the residual frequencies are observed. 25 One method of manufacturing hydrazine (N 2 H 4 ) involves the action of sodium chlorate(i) on excess ammonia at 443 K and 50 atm. The yield is normally around 80% but, if just 1 part per million of copper(ii) ions is present, the yield drops to 30%. The most likely explanation for this is the ability of copper(ii) ions to form complex ions with ammonia. catalyse reactions producing other nitrogen compounds. reduce the hydrazine as it is formed. reduce the sodium chlorate(i).

12 26 Platinum forms a complex with the formula Pt(NH 3 and chromium forms a complex ion with the formula rl 4. (a) onsidering the shapes of these complexes, both complexes are square planar. (1) both complexes are tetrahedral. Pt(NH 3 is tetrahedral and rl 4 is square planar. Pt(NH 3 is square planar and rl 4 is tetrahedral. (b) onsidering the structures of these complexes, both complexes form stereoisomers. (1) neither complex forms a stereoisomer. Pt(NH 3 forms a stereoisomer but rl 4 does not. rl 4 forms a stereoisomer but Pt(NH 3 does not. (c) onsidering the bonding between the central atom and the ligands in these complexes, the bonding in both complexes is dative covalent. (1) the bonding in both complexes is ionic. the bonding in Pt(NH 3 is dative covalent and in rl 4 is ionic. the bonding in Pt(NH 3 is ionic and in rl 4 is dative covalent. (Total for Question = 3 marks)

13 27 The transition metal complex Pt(NH 3 exists as two geometric isomers. This is because the complex is square-planar. is tetrahedral. contains a double bond. is octahedral. (Total for Question 1 mark) 28 hydrated transition metal ion is colourless. Which of the following could be the electronic configuration of this ion? [r] 3d 5 4s 2 [r] 3d 8 [r] 3d 10 4s 2 [r] 3d 10 (Total for Question 1 mark) 29 Which of the following species is not able to act as a ligand in the formation of transition metal complexes? 6 H 5 NH 2 NH 3 NH 2 H 2 H 2 H 2 NH 2 + NH 4 (Total for Question 1 mark)

14 30 The element zinc, with electronic configuration 1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2, is not regarded as a transition element because the oxide of zinc is amphoteric. none of its ions has an unpaired electron in the d-subshell. it does not readily form complex ions. it has a boiling temperature low enough for it to be easily distilled. (Total for Question 1 mark) 31 What type of bonding occurs between the metal ion and ligand in the complex ion [u(h 2 O) 6 ] 2+? Metallic Ionic Hydrogen ative covalent (Total for Question 1 mark)