1.the periodic table Flashcards
Colour of Chlorine in water(polar) and cyclohexane(non-polar)
colourless in polar water colourless in non-polar cyclohexane
Colour of Bromine in water(polar) and cyclohexane(non-polar)
yellow-orange in polar water yellow-orange in non-polar cyclohexane
Colour of Iodine in water(polar) and cyclohexane(non-polar)
brown in polar water purple in non-polar cyclohexane
Most powerful group 7 O.A
F2 is the most powerful and so on they can oxidise lower reactivity halide ions
colours and states of the pure halides
F2- pale yellow gas CL2- dense green gas Br2- orange/brown liquid (same as a gas) I2- dark grey sold (purple gas)
Reactivity series in group 7 and why.
Reactivity decreases down the group. As to form ions they have to gain 1e- and the ionic radi are smaller for the higher up atoms which means e- are more strongly attracted to it. SHieldiung e- and neuclear charge cancel out.
Why is the ionic radis bigger in halogens then the atomic radius?
The ions are larger because the repulsion added when all the orbitals are full expands the radius .
what does isoelectronic mean
same number of valence e-
disproportination
when the same element gets simultaneously oxidised and reduced in a reaction.
Form a compound that is a disinfectant for pools, drinking water use….
NaOH + Cl not water +CL
Cold!!! forming a disinfectant equation.
Cl2+ 2NaOH –> NaCL + NaClO + H2O
hot!!! forming a disinfectant equation.
3Cl2+ 6NaOH –> 5NaCL + NaClO3 + 3H2O
Cl2+H2O–>
HCl + HClO
What colour are group 1&2 compounds
What colour are group 1&2 solutions
compounds - white
solutions - coulourless
Group 2 reactivity
increases as you go down the group, becuas eto react they need to lose e-
Atomic radius increase which decreses attraction and makes it easier to lose e- . SHieldiung e- and neuclear charge cancel out
Thermal decompostion of group 2 carbonates
MCO3 –> CO2 + MO
CO2 testing with limewater
( Ca(OH)2+CO2–>CaCO3)
Group 2 thermal decomposition order and why.
Easy-MgCO3 Gets harder down the group becuase they are more thermally stable and are harder to decompose.
Uses of the group 2 hydroxides Ca(OH)2 and Mg(OH)2
Ca(OH)2 - is used by farmers and garderners as ‘lime’ to neutralise acid soils.
Mg(OH)2- is used in ‘milk of magnesia’ in order to relieve indigestion, it nutralises excess stomach acid.
Group 2 oxides and hydroxides are….
bases…. they are neutralised by acids to form a salt and water.
soulubilty trend in group 2 hydroxides
they become more soluble down the group, this means lower down metal hydoxides make a more alkali solution.
Halide ions with silver nitrate solution.
chloride ions-White (goes coulourless in all ammonia)
Bromide ions- Cream (goes coulourless in conc ammonia)
Iodide ions- Yellow
Group 2 metal + water
M + 2H2O–> M(OH)2+H2
uses of ionic halide compounds.
NaCl-common salt
NaF(and tin fluoride) added to toothpaste to prevent decay.
CaF2 crystals useds to make lenses that focus infrared light.
What is a disadvantage to using chlorine in water treatment.
chlorine is toxic/poisonous and could form chlorinated hydrocarbons (carcinogens)
Define periodicity
a repeating pattern of properties shown across different periods.
