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37 Cards in this Set
- Front
- Back
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what are the features of fluorine |
pale yellow gas and its very reactive |
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what are the features of chlroine |
green reactive gas and poisonous in high concentration |
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what are the features of bromine |
red liquid that gives off dense brown poisonous fume |
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what are the features of iodine |
shiny grey solid sublimes to purple gas |
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fluorine does not follow the trend of the halogens explain how and why |
F-F bonds are weak and it has a small size of fluorine atom leads repulsion between non-bonding electrons because they are too close |
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what happens to the size of the atoms going down the group |
it gets bigger and each element has 1 extra filled main level of electrons |
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what is the definition of electronegatvity |
it is a measure of the ability of an atom to attract electrons towards itself within a covalent bond |
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what happens to the electronegativty going down the group and why |
decreases because the atomic radius increases there the attraction between the nucleus and electrons is weaker |
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what happens to the melting point going down the group and why |
increases larger atoms have more electrons so this means that the van deer waal forces between the molecules are stronger |
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how do halogens react |
they gain electrons and become negative ions (-1) |
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what happens to the oxdising ability going up the group |
it increases |
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a halogen that is a strong oxidising agent can |
displace a halogen that has a lower oxidising power from one of its compound |
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what is a displacement reaction |
halogens will react with metal halides in solution in such a way that the halide in compound will displaced by a more reactive |
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describe halide ions as reducing agents |
they lose electrons and become halogen molecules |
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what are the observation for sodium chloride/ sodium fluride |
steamy fumes of hydrogen chloride and solid product is sodium hydrogencarbonagte |
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what is the equation when sodium chloride reacts with sulfuric acid |
NaCl(s) + H2SO4(l) = NaHSO4(s) + HCl(g)
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what is the equation when sodium fluoride reacts with sulfuric acid |
NaF(s) + H2SO4(l)= NaHSO4(s) + HF(g)
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expalin why the reaction is an acid base reaction and why NaF(s) + H2SO4 (l)= NaHSO4 (s) + HF(g) |
because there is no change in the oxidation number because fluoride is a weak reducing agent to reduce the sulfur this is the same for chloride |
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what are the observations for sodium bromide |
steamy fumes of hydrogen bromide brown fumes of bromine colorless sulfur dioxide |
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what are the two reactions for sodium bromide |
Acid- base step: NaBr(s) + H2SO4(l) = NaHSO4(s) + HBr(g)
Redox step: 2HBr + H2SO4 = Br2(g) + SO2(g) + 2H2O(l) |
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what role does H2SO4 play in acid base reaction |
acid |
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what role does HBr play in redox reaction |
oxidising agent |
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what are the observations for an sodium iodide reaction |
black solid from iodine steam fumes of hydrogen iodide bad egg smell fro hydrogen sulfide yellow solid sulfur colorless sulfur dioxide gas |
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what is the equation for sodium iodide reacting with sulfuric acid |
NaI(s) + H2SO4(l)= NaHSO4(s) + HI(g)
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what is the oxdation half equation for sodium bromide |
Ox ½ equation 2Br - = Br2 + 2e
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what is the reduction half equation for sodium bromide |
H2SO4 + 2 H+ + 2 e- → SO2 + 2 H2O
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what is the oxidation half equation for sodium iodide |
Ox ½ equation 2I - = I2 + 2e
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what role does H2SO4 in sodium iodide reaction |
acid and oxdising agent |
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what is the equation when water reacts with chlroide |
Cl2(aq) + H2O(l) = HClO(aq) + HCl (aq) the is a reversible reaction |
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why is this a dispropotions reaction Cl2(aq) + H2O(l) HClO(aq) + HCl (aq) |
Chlorine is both simultaneously reducing and oxidising
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what is a disproprtions reaction |
Disproportionation is the name for a reaction wherean element simultaneously oxidises and reduces.
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what is chloric (1) used for |
it is an oxdising agent which oxdises bacteria to kill them |
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what is the reaction when chloride reacts with water in the sunlight |
2Cl2 + 2H2O = 4H+ + 4Cl- + O2
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explain why swimming pools outside need to be refilled with chloride frequently |
chlriide is rapidly lost in the sunlgiht |
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what is an alternative method instead of using chloride in the swimming pool and what is the equation |
sodium (or calcium) chlorate 2Cl2 + 2H2O = 4H+ + 4Cl- + O2 |
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when using sodium chlorate why is it important monitor the swimming pool |
the equilibrium moves to the left and HClO is removed and so it becomes slightly acidic so it it becomes too acidic it can corrode the metal and harm the swimmers |
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what is the observations when chloride reacts with sodium hydroxide and what is the equation and what is is it used for |
colour of halogen solution will fade to colourless Cl2(aq) + 2NaOH(aq) = NaCl (aq) + NaClO (aq) + H2O(l) can be used as a bleach |
