Groups
- Created by: [email protected]
- Created on: 22-02-19 14:01
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- Groups
- Group 2
- Reactions
- They react with water to produce metal hydroxides and hydrogen
- E.g. Ca(s) + 2H2O(l) --> Ca(OH)2(aq) +H2(g)
- Burn in oxygen to form solid white oxides
- E.g. 2Ca(s) +O2)g) --> 2CaO(s)
- Decompose to form G2 oxide and CO2(g)
- E.g. CaCO3(s) --> CaO(s) +CO2(g)
- They react with water to produce metal hydroxides and hydrogen
- Trends
- Solubility
- Compounds of G2 metals that contain singly charged -ve ions (e.g. OH-) increase in solubility down the group
- Compounds of G2 metals that contain doubly charged -ve ions (e.g. (CO3)2- and (SO4)2-) decrease in solubility down the group
- Reactivity
- Get more reactive down the group because outermost electrons are further from the nucleus so more easily lost
- Thermal stability
- Increases down G2
- Large cations cause less distortion of the carbonate anion since they have a lower charge density so are more stable
- Increases down G2
- Solubility
- Reactions
- Group 7
- Trends
- Reactivity
- Less reactive down the group since outer-shell electrons further from nucleus so more shielding and less attraction to positive nucleus so harder to attract an electron
- Volatility
- Get less volatile down G7 since RAM increases so number of IDIDs increases
- Solubility
- Since they're covalent and non-polar they have low solubility in water but will dissolve in organic solvents e.g. hexane
- Reactivity
- Halogen-Halides
- If Br2 is formed: yellow/orange in (aq) and orange/red in hexane
- If I2 is formed: brown in (aq) and pink/violet in hexane
- Hydrogen-Halides
- Production
- All can be made by adding conc H3PO4(aq) to a solid ionic halide
- Only HCl can be made from H2SO4(aq)
- Iodine and bromine are strong enough reducing agents to reduce the sulfur
- Bromide ions oxidise to Br2(g) and the sulfuric acid is reduced to SO2(g)
- Iodide oxides to I2(g) and sulfuric acid is reduced to H2S
- Iodine and bromine are strong enough reducing agents to reduce the sulfur
- Reactions
- Dissolve in water to form strong acids (except HF which doesn't fully dissociate so is weak acid)
- React with ammonia to form an ammonium halide
- E.g. HF(aq) + NH3(aq) --> NH4F(aq)
- HBr and HI reduce H2SO4(aq)
- HBr reduces H2SO4 to SO2
- HI reduces H2SO4 to H2S
- Thermal stability
- Stability decreases down G7 due to decreasing strength of Hydrogen-Halide bonds. Halogen atoms get bigger down the group so bonding electrons further from nucleus
- Production
- Haloalkanes
- Boiling points
- Increase down G7 since number of IDIDS increase
- Reactions
- Undergo nucleophilic substitution with OH-,H2O and NH3
- Reactivity
- Although the C-F bond is the most polar it has the highest bond enthalpy so reactivity increases down the group
- Formation
- Boiling points
- Trends
- Group 2
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