Group 7 Flashcards
describe the trend in atomic radius
- atomic radius increases down the group
- due to additional electron shells
describe the trend in oxidising power
- oxidising power decreases down the group
- increase in shielding + atomic radius makes it harder to attract electrons
describe the trend in boiling and melting temperature
- melting and boiling temperature increases down the group
- due to increase in relative atomic mass, increasing strength of London forces in the simple covalent molecule so more energy is required to overcome them
describe the trend in reactivity
- reactivity decreases down the group
- due to increase in atomic radius
- due to additional electron shells the positive attraction of the nucleus decreases
- harder to attract an electron
describe the trend in electronegativity
- electronegativity decreases down the group
- atomic radius + electron shielding increase
- electrons are more easily removed due to less strong attraction to the nucleus
describe the trend in reducing power
- reducing power increases down the group
- electrons are easier to lose from larger ions
- due to increased shielding and atomic radius
what is involved in a redox reaction
halide + sulfuric acid
NaF + H2SO4 –>
NaHSO4 + HF
NaCl + H2SO4 –>
NaHSO4 + HCl
what are HCl, HF, HI and HBr
misty fumes
why is there only one reaction with HF and HCl when reacting with H2SO4
because they aren’t strong enough to reduce the H2SO4 any further so there are no further reactions
all reactions of NaBr + H2SO4
NaBr + H2SO4 –> NaHSO4 + HBr
2HBr + H2SO4 –> Br2 + SO2 + 2H2O
What is Br2
orange fumes
what is SO2
choking fumes
describe the reaction between HBr and H2SO4
HBr reduces HsSO4
all reactions of NaI + H2SO4
NaI + H2SO4 –> NaHSO4 + HI
2HI + H2SO4 –> I2 + SO2 + 2H20
6I2 + SO2 –> H2S + 3I2 + 2H2O
what is H2S
toxic gas
describe what happens in the reaction between NaI + h2SO4
- HI reduces H2SO4
- HI further reduces the SO2
What reaction is chlorine with water
disproportionation
Cl2 + H2O (with oxidation numbers)
Cl2 + H2O –> ClO- + Cl- + 2H+
(0)—————–(+1)—-(-1)——–
write the reaction involved in the formation of bleach (sodium chlorate (I))
2NaOH + Cl2 –> NaClO + NaCl + H2O
—————(0)———(+1)——-(-1)——-
write the reaction between chlorine and hot, concentrated sodium hydroxide
3Cl2 + 6NaOH –> NaClO3 + 5NaCl + 3H2O
-(0)————————–(+5)———(-1)————-
what forms when you react Chloride ion with AgNO3
white precipitate (AgCl)
what forms when you react bromide ion with AgNO3
cream precipitate (AgBr)
what forms when you react iodide ion with AgNO3
yellow precipitate (AgI)
what happens when you react AgCl with dilute NH3
precipitate dissolves
what happens when you react AgI and AgBr with dilute NH3
nothing happens
what happens when you react concentrated NH3 with Br- ion and Cl- ion
precipitate formed from AgNO3 dissolves
what happens when you react concentrated NH3 with I- ion
nothing happens
what do hydrogen halides react with ammonia gas to form
ammonium salts
HCl + NH3 –>
NH4Cl
what is NH4Cl
a strong acid in solution
what forms when you react hydrogen halides with water
dilute acids which disassociate to release halide and hydrogen ions
what do hydrogen ions form with water
hydroxonium ions, creating an acidic solution
HCl + H2O –>
Cl- + H30+
What colour and state is fluorine at Room Temperature
- yellow
- gas
What colour and state is chlorine at room temperature
- green
- gas
What colour and state is bromine at room temperature
- brown
- liquid
What colour and state is iodine at room temperature
- dark grey
- solid
What electron configurations do halogens all have
S2P5 outer shell configurations
What type of covalent molecules are halogens
Diatomic covalent (two halogen atoms share a pair of electrons)
Describe halogens in terms of displacement
A more reactive halogen will displace a less reactive halogen from its halide salt
