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33 Cards in this Set
- Front
- Back
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how does atomic radius change along a period and why |
atomic radius decreases due to an increase in nuclear charge (Number of protons) |
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how does atomic radius change as you go down a group? |
increases due to increase in electron shells |
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How is the ionisation energy trend different in aluminium |
It decreases despite and increase in atomic radius outermost electron sits in a higher energy sub shell further from the nucleus than that of magnesium |
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why is the ionisation energy of sulphur the same as phosphorus in period three |
they both have outer shell electrons in the 3p orbital in sulphur the two electrons in the 3P orbital naturally repel so less energy is needed |
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why does silicon have such a high melting point in period three |
macro molecular structure equals very strong covalent bonds |
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Why are you phosphorus sulphur and chlorine have low melting points in period 3 |
simple covalent molecules with a weak Vanderwall forces |
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how does atomic radius change as you go down group two |
Increases |
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how does ionisation energy change as you go down group two |
Decreases due to increase of shielding so nuclear attraction is lower |
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describe the trend of melting points down group two |
decreases due to shielding |
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how does reactivity change as you go down group two and why |
increases due to shielding so electrons are easier to remove |
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describe the test for sulphates |
add HCL to remove carbonates are barium chloride White precipitate |
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Give the ionic equation for neutralisation |
H+ (aq) + OH- (aq) —> H2O (l) |
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how do boiling points change as you go down group 7? |
Increases due to an increase of Vanderwall forces and size of atoms |
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Describe the trend of electronegativity as you go down group 7 |
Decreases as atoms get larger and shielding increases |
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describe the trend of reactivity as you go down group 7 |
reactivity decreases due to lower atomic radius so e- harder to remove |
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Equation for the production of bleach |
chlorine + sodium hydroxide —> Sodium chlorase + sodium chloride + water |
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Test for halides |
add nitric acid add silver nitrate ppt forms |
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What precipitate forms from iodide ions in halide test |
Yellow |
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What precipitate forms from bromidein halide test |
cream |
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What precipitate forms from chloride ions in halide test |
white |
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Test for sulphates |
add HCL to remove carbonate add barium chloride white precipitate (barium sulfate is insoluble) |
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Test for carbonates |
add HCL CO2 turns lime water cloudy |
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what is ionisation energy? |
min amount of energy required to remove 1 mole of e- from 1 mole of atoms in a GASEOUS state |
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is ionisation energy endo or exothermic? |
endothermic as it requires energy and has a +ive value |
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how does ionisation energy change down a group? |
decreases due to an increase in atomic radius so outershell e- is further from nucleus attraction |
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how does ionisation energy change along a period? |
increases as there are more protons so higher nuclear attraction |
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why do Na, Mg and Al have such high mtp in period 3? |
metallic bonds greater force of attraction between +ions and e- |
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describe the flame test for group 2 cations and give results |
dip nichrome wire in HCl, dip into sample, place on blue flame Ca2+ - dark red Ba2+ - green Sr2+ - red |
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describe the test for ammonium compounds using litmus paper |
add NaOH and heat gently if ammonia is present then ammonia gas will be produced and will turn red litmus paper blue |
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describe the test for hydroxides using litmus paper |
hydroxides are alkaline so red litmus paper turns blue |
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what happens when the halide ion cl- reacts with sulfuric acid? |
it forms NaHSO4 + HCl (white misty fumes) |
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what happens when the halide ion Br- reacts with sulfuric acid? |
NaBr + H2SO4 = NaHSO4 + HBr reduced further 2Br- + H2SO4 + 2H+ = SO2 +2H2O + Br2 orange vapour of Br produced |
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what happens when the halide ion I- reacts with sulfuric acid? |
NaI + H2SO4 = NaHSO4 + HBr reduced further 6I- + H2SO4 + 6H+ = S +4H2O + 3I2 Yellow solid produced S is reduced further H2SO4 + 8H+ + 8I- = 4I2 + H2S + 4H2O rotten egg smell of H2S |
