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| Question | Answer |
| What is thermal decomposition? | A reaction where in which a compound dissolves upon heating. |
| What is an ionic precipitation reaction? | A reaction which produces a solid precipitate on mixing two solutions containing ions. |
| Which acids are soluble in water? | All common acids. |
| Which metal hydroxides are soluble in water? | Alkalis: sodium hydroxide, potassium hydroxide... Calcium hydroxide is slightly soluble. |
| Which metal carbonates are soluble? | Alkalis: sodium carbonate, potassium carbonate... |
| Which salts are soluble in water? | All nitrates All chlorides (apart from silver and lead chloride) All sulfates (apart from barium and lead sulfate) All sodium, potassium and ammonium salts |
| How does atomic radius change in groups 1 and 2? | It increases down the group because there is one more shell each period. |
| Are the ions of group 1 and 2 elements bigger or smaller than their atoms? | They are smaller because they lose their valence electrons so have one less shell. Also there is one or two more protons than electrons in the ions, so there is a greater attraction to the positive nucleus. |
| Which is bigger: a group 1 atom or a group 2 atom? | A group 1 atom. The effective attraction of group 1 is +1, group 2 is +2 so there is a greater attraction to the positive nucleus. |
| Which is bigger: a group 1 ion or a group 2 ion? | A group 1 ion. Less of a positive charge means less of an attraction to the nucleus. |
| What is a base? | An 'anti-acid'- the chemical opposite of an acid. They accept hydrogen ions. |
| What are the characteristics of group 1 carbonates? | White bases Less soluble as you go down the group Most do not decompose on heating-exception is lithium carbonate which decomposes to the oxide and CO2. |
| What are the characteristics of group 1 nitrates? | White crystalline solids Very soluble On heating they melt then decompose as far as the nitrate Lithium decomposes to the oxide, NO2 and O2 |
| What are the flame colours of Li, Na and K? | Li - Bright red Na - Bright yellow K- Lilac |
| Describe how group 2 metals react with oxygen: | They burn to form white ionic oxides (apart from beryllium). Mg - intense white flame Ca - red flame Ba - green flame (forms a peroxide) |
| What is a basic oxide? | A metal oxide that reacts with acids to form a salt and water. |
| How does the solubility of group 2 hydroxides change as you go down the group? | It increases. |
| What are the characteristics of group 2 carbonates? | Insoluble in water React with dilute acids Decompose on heating to give the oxide and CO2 Thermal stability increases down the group |
| What are the characteristics of group 2 nitrates? | Colourless crystalline solids Very soluble in water Thermal stability increases down the group |
| What are the characteristics of group 2 sulfates? | Colourless solids Less soluble down the group |
| What are the flame colours of group 2 elements? | Be - no colour Mg - no colour Ca - brick red Sr - bright red Ba - pale green |
| What is meant by thermal stability? | An indication of the ease with which compounds decompose on heating. |
| What does polarising power mean? | An indication of the extent to which a positive ion is able to distort the electron cloud around a neighbouring negative ion. |
| What two factors affect polarising power? | Charge on metal ion (larger charge = greater power) Size of metal ion (smaller = greater power) |
| Explain the trend in the thermal stability of metal carbonates and nitrates: | Charge of metal ion stays the same down the group but size increases. Hence polarising power weakens. There's less of a pull on the electrons and bonding is less distorted, making it harder to break up the anion. So, the thermal stability increases down the group. |
| Describe the appearance of the halogens under standard conditions: | Chlorine: yellow green gas Bromine: dark red liquid Iodine: dark grey solid |
| How does oxidising power change as you go down the group? | It decreases down the group because the first electron affinity decreases. |
| How does boiling point change down the group? | It increases because the inter molecular forces (London forces) increase because there are more electrons each time. |
| How does first electron affinity change as you goes down the group? | It decreases because there is more shielding, the atomic radius is bigger and the outer electron is at a higher level. |
| How does solubility change as you go down the group? | Water has hydrogen bonding but halogens only have London force so solubility is low. Fluorine has the weakest hydrogen bonds so is the most soluble. Solubility decreases down the group as London forces increase. |
| What are the reactions of sodium halides with conc sulfuric acid? | |
| What are the properties of silver halides? | |
| What are the properties of hydrogen halides? | Colourless gases at RT which fume in moist air Very soluble, forming acidic solutions which ionise completely Strong acids |
| What is formed when halogens reacts with water? | Chlorine: Chlorine oxanions (HClO) Bromine: Similar Iodine: Barely any reaction |
| Explain the difference between strong/weak and concentrated/dilute in acids? | Strength: degree of dissociation (ionising in solution) Concentration: moles or grams per volume |
| Why does the small amount of MgO on Magnesium ribbon have to be removed before any reactions? | Otherwise both the Mg and the MgO will react but at different rates. |
| Why don't group 1 carbonates generally decompose on heating? | They only have a 1+ charge which isn't enough to polarise the carbonate ion. Lithium is the exception because i |
| Explain how flame colours are created? | The heat causes the electron to move to a higher energy level. It is unstable at this level so drops down again. Energy is emitted when it does this, in the form of visible light. |
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