Applied science unit 5 transition metals 5.0 / 5 based on 1 rating ? Applied ScienceUnit 5 / transition metalsBTEC NationalAll boards Created by: KlaudiaJaglaCreated on: 18-09-19 14:19 What are transition metals? The d block elements. They have an incomplete d-sub-shell 1 of 35 What can transition metals form? One or more ions 2 of 35 What happens when transition metals react? Lose electrons to form positive ions. 3 of 35 What are the properties of transition metals? - coloured compounds - variable oxidation states - catalysis - complex ion formation 4 of 35 Why are the properties of transition metals unique? The incomplete d sub-shell 5 of 35 What sub-shells are filled first going across period 4 (transition metals)? 4s-sub-shell fills before the 3d-sub-shell 6 of 35 Why are the sub-shells filed in that order? Sub-shells energy levels overlap 7 of 35 What subshell are electrons lost from transition metals? Lose 4s electrons before their 3d electrons. 8 of 35 What can all transition metals form? 2+ ions (when losing the two electrons from the 4s orbital) 9 of 35 How do transition metals have variable oxidation states? 4s orbital and 3d orbital have close energy levels & overlap. Electrons can be lost to form stable ions 10 of 35 Why are compounds containing transition metals coloured? When electrons jump from one orbital to another, light is emitted (from the partially filled d-orbitals) 11 of 35 Why do transition metals make good catalysts? Ability to change oxidation state 12 of 35 Why do transition metals form complex ions? Empty valence-shell orbitals which can accept pairs of electrons from ligands 13 of 35 What do transition metals form in solution? Complex ions 14 of 35 What is a "complex ion"? A central transition metal atom or ion, surrounded by ligands and bonded with dative covalent bonds 15 of 35 What is a "ligand"? A molecule or ion that can donate a pair of electrons to form a dative covalent bond 16 of 35 What is a dative covalent (co-ordinate) bond? One atom proved both of the shared electron in the bond. 17 of 35 What is a "catalyst"? A substance that speeds up a reaction and can take part in the reaction but is left unchanged at the end. 18 of 35 How do catalysts speed up reactions? They provide another route for the reaction to take place which has a lower activation energy. 19 of 35 What is "activation energy"? Minimum amount of energy needed by reactants for collisions to result in reaction taking place 20 of 35 What is a heterogeneous catalyst? A catalyst in a different phase to the reactants 21 of 35 What is a homogeneous catalyst? A catalyst in the same phase as the reactants 22 of 35 What is the contact process? A process used to make sulfuric acid 23 of 35 What catalyst is used in the contact process? Vanadium (V) oxide 24 of 35 How is vanadium (V) oxide used in the contact process? Catalyses the reaction of sulfur dioxide to sulfure trioxide 25 of 35 What is the equation for vanadium (V) oxide catalysing the reaction? SO2 + 1/2O2 = SO3 26 of 35 Why is vanadium (V) oxide used? Its variable oxidation state creates a different route with a lower activation energy 27 of 35 What happens first when the catalyst is used in the contact process? Sulfur dioxide is oxidised to sulfur trioxide & vanadium (V) oxide is reduced to vanadium (IV) oxide 28 of 35 What is the equation for the first part of the catalyst being used in the contact process? SO2 + V2O5 = 2SO3 + V2O4 29 of 35 What happens to the vanadium (IV) oxide afterwards? It is oxidised with oxygen to produce vanadium (V) oxide, which is ready to catalyse the next reaction 30 of 35 What is the equation for vanadium (IV) oxide afterwards? V2O5 + 1/2O2 = V2O5 31 of 35 What is the haber process? A method used to produce ammonia 32 of 35 What is the equation for the haber process? N2 + 3H2 = 2NH3 33 of 35 What catalyst is used in the Haber process? Iron (Fe) 34 of 35 How does the iron catalyst speed up the reaction (haber process) ? Nitrogen and hydrogen molecules react on the surface of the iron catalyst 35 of 35
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