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Descrição
FlashCards por Madeleine.Dc, atualizado more than 1 year ago
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Criado por Madeleine.Dc
aproximadamente 11 anos atrás
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| Questão | Responda |
| What are transition metals? | A d-block element that forms an ion with an incomplete d sub-shell. |
| Why are scandium and zinc not transition metals? | Scandium has a completely empty sub shell and zinc has a completely full d sub shell. The d sub shell must be incomplete for it to be a transition metal. |
| How do you write electron configurations for elements and ions? |
Image:
mads (image/png)
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| Why do chromium and copper not follow the electron configuration pattern? | Electron repulsion in the outer electrons are minimised resulting in increased stability of the atoms. |
| What is the electron configuration of chromium? | 1s2 2s2 2p6 3s2 3p6 4s2 3d5 |
| What is the electron configuration of copper? | 1s2 2s2 2p6 3s2 3p6 4s1 3d10 |
| What happens to a transition element in a reaction? | They lose electrons to form positive ions; losing their 4s electrons before their 3d electrons. |
| Why are 4s electrons lost first? | They have a higher energy. |
| What is the difference between a d block element and a transition element? | Transition elements are elements where the d orbital is incomplete whereas d block elements have a d orbital as the highest energy and this can be empty or full. |
| Write the electron configuration for: Cr, Mn2+, Sc3+ and Ti | 1s2 2s2 2p6 3s2 3p6 4s2 3d5 1s2 2s2 2p6 3s2 3p6 3d5 1s2 2s2 2p6 3s2 3p6 1s2 2s2 2p6 3s2 3p6 4s2 3d2 |
| Physical properties of transition metals. | Shiny in appearance High densities High melting points High boiling points |
| What do transition metals exist as when they are solids? | Giant metallic lattices, containing delocalsised electrons which can move to conduct electricity. |
| Uses of transition metals | Coins Joint replacements Telephone boxes Alloyed for use in construction |
| Transition elements from titanium to copper can form ions with how many oxidation states? | Two or more |
| Why do transition metals form compounds with ions in the +2 oxidation state? | As they lose the 2 electrons from the 4s orbital. (Higher energy level than that of 3d orbital, although close together) |
| Why are compounds containing transition metal ions coloured? | Some of the wavelengths of visible light are absorbed. The colour is a combination of the wavelengths that have not be absorbed. |
| What is a catalyst? | A substance that increases the rate of a reaction by providing an alternative route with a lower activation energy. |
| Why are transition metals good catalysts? | They provide a surface on which a reaction can take place. Transition metal ions have the ability to change oxidation states by gaining or losing electrons. They then bind to reactants forming intermediates as part of a chemical pathway with a lower activation energy. |
| Haber Process | N2(g) + 3H2(g) <=> 2NH3(g) Iron metal is the catalyst |
| Contact Process | 2 SO2(g) + O2(g) ⇌ 2 SO3(g) Vandium Oxide catalyst, V2O5 - V has the 5+ oxidation state |
| Hydrogenation of Alkenes | Unsaturated compounds to saturated compounds. Nickel catalyst, lowers the temperature and pressure. |
| Decomposition of hydrogen peroxide. | 2H2O2 ---> 2H20 + O2 Manganese oxide is the catalyst with +4 oxidation state. |
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