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Flashcards by megan trent, updated more than 1 year ago
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| Question | Answer |
| what happens when group 2 elements react with water | they produce a metal hydroxide [(OH)2]and hydrogen |
| what happens when group 2 elements react with oxygen | they produce a solid white oxide |
| what happens when group 2 elements react with chlorine | they produce a solid white chloride |
| how do oxides and hydroxides react with water | oxides form hydroxides hydroxides form the same hydroxide (no change) |
| how do oxides and hydroxides react with dilute acid | both oxides and hydroxides form a metal chloride and water |
| what are solubility trends down group 2 | for sulphates, solubility increases going UP for hydroxides, solubility increases DOWN |
| what is thermal stability | how much heat it takes to break something down. higher thermal stability means more energy needed |
| what are thermal stability trends down a group | down a group, elements get more thermally stable. this is because they are larger, so the charge is more spread out, causing less distortion |
| how thermally stable is group 2 | much less than group 1. this is because they have a higher charge (2+) so cause more distortion |
| describe how group 1 carbonates and nitrates decompose | group 1 carbonates don't decompose, they are to thermally stable. group 1 nitrates decompose to form a nitrate and oxygen. |
| describe how group 2 carbonates and nitrates decompose | group 2 carbonate decompose to form an oxide and carbon dioxide. group 2 nitrates decompose to form an oxide, nitrogen dioxide and oxygen |
| how can we test for thermal stability (in nitrates and carbonates) | see how long it takes for the carbonate to form CO2 (add it to limewater to tell). and see how long it takes for the nitrate to form oxygen (try to relight a splint) |
| what are the fame tests for group 1 and 2 | little children stand yelling potatoes potatoes come read bible of god. lithium crimson sodium yellow potassium purple calcium red barium green |
| what is the explanation for flame test colours | as energy is absorbed from the flame, electrons move to higher energy levels. as they fall back down, light is releases. the colours are determine by how far they fall. |
| what kind of bonding is present in group 1 and 2? | metallic |
| What is the trend in reactivities of group 1 and 2 descending the group? | The reactivity increases as the ionisation energy decreases |
| Why is beryllium chloride covalent but barium chloride ionic? | beryllium has a larger ionisation energy so it requires much more energy to remove the electrons in the outer shell |
| what is more reactive, Mg or Ba? | Ba as it has a lower ionisation energy, so it is easier for it to react, as it will lose electrons easier |
| Why does Mg have a high boiling point? | it has lots of delocalised electrons and the smallest radius |
| what happens to the ionic radii of the 2+ ion on descending the group? | increases as there is more shielding |
| Reactions with oxygen Mg with oxygen | safety - look through cobalt glass reason- UV and bright white light observation- Mg illuminating and turns white equation - 2Mg + O2 ----> 2MgO |
| What happens when MgO is placed in water? | it reacts to form magnesium hydroxide. Universal indicator turns blue so its alkaline |
| what do group 2 metals react with chlorine to form? | a chloride example - magnesium and chlorine produces MgCl2 |
| reactions with water of group 1 and 2 metals Mental + water -----> | hydroxide + hydrogen |
| the reaction of Mg and steam | Mg will react very slowly in cold water to form a suspension of Magnesium hydroxide and hydrogen. With steam it will form the oxide and hydrogen |
| reactions of group 2 oxides and hydroxides Acid + base -------> | salt + water |
| oxide + water ------> | hydroxide |
| oxide + acid ------------> | salt + water |
| metal + water---------> | salt + hydrogen |
| pattern of solubility | if the anion and cation sizes are similar, the lattice enthalpy is relatively high and the salt will not be soluble. |
| which ion is more polarising, group 1 or 2? | group 2 as its smaller and a bigger charge |
| which group forms more stable carbonates? | group 1, because they are least polarising |
| decomposition of a group 2 carbonate to a group 2 oxide | a smaller cation is more polarising and distorts the electron cloud, Co2 is given off leaving the oxide the smaller the metal ion the less stable the carbonate |
| Thermal decomposition of group 1 and 2 nitrates | the nitrate ions can be "pulled apart'' in the same way as the carbonate ion |
| Group 2 nitrates decompose fully to form? | the oxide + nitrogen dioxide + oxygen |
| group 1 nitrates decompose partially to form? | the nitrate salt + oxygen |
| lithium nitrate (group 1) is an exception , why? | it forms the oxide + nitrogen dioxide + oxygen lithium nitrate does this because its so polarising |
| Explain why magnesium nitrate decomposes more readily on heating than potassium nitrate? | Mg ion have smaller radius and a 2+ charge compared to K (larger radius and 1+) So Mg is more polarising so nitrate can be pulled apart more easily potassium nitrate is more stable, so more energy is needed for thermal combustion |
| ionisation energy decreases down group 2 | |
| the oxides and hydroxides are bases... | |
| the oxides and hydroxides so they form alkaline solutions and neutralise acids | |
| here's how to do a flame test: | |
| group 2 elements react with water, oxygen and chlorine | |
| thermal stability of carbonates and nitrates changes down the group | |
| group 1 vs group 2 thermal stability |
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