Grade 99 Edexcel Combined Science: Chemistry Paper 2, Most detailed notes you'll ever find, better than the textbook bro
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Course
Science
Institution
GCSE
**NOT A SUMMARY, THIS IS IN COMPLETE DETAIL**
I attained 99 in Combined Science solely through this self made resource of mine. I have painstakingly gathered information from every EDEXCEL specific resource I could lay my hands on (including seneca, pmt, savemyexams, lit every single video on each...
Combined Edexcel CHEMISTRY PAPER 2
**NOT A SUMMARY, THIS IS IN COMPLETE DETAIL**
I attained 99 in Combined Science solely through this self made resource of mine. I have
painstakingly gathered information from every EDEXCEL specific resource I could lay my hands on
(including seneca, pmt, savemyexams, lit every single video on each topic i could find and the
EDEXCEL textbook itself) in order to create this incredibly precise document. It meets every single
specification point in meticulous detail, including diagrams and lengthy explanations where needed. It
is the boiling pot of absolutely every single thing you need to know, nothing more n nothing less, to
seize your 99 in GCSE Combined Science.
Key:
- Boldened: Specification point itself
(Key Concepts is in the Paper 1 bundle)
(Unit 5 is in GCSE chemistry only)
Unit 6: GROUPS IN THE PERIODIC TABLE:
Group 6
6.1 Explain why some elements can be classified as alkali metals (group 1), halogens
(group 7) or noble gases (group 0), based on their position in the periodic table
Groups/columns in their periodic table can be classified as specific groups as alkali metals,
halogen or noble gases, because they have the same number of electrons in their outer shell
(position in the periodic table determines this) therefore they have the same chemical
properties
6.2 Recall that alkali metals
a are soft
b have relatively low melting points
> They are soft metals and can be cut easily with a knife or blade, they become softer as
you go down the group.
> They have low melting points which decrease as you go down the group. This is due to the
atoms getting bigger as their period number increases therefore, they have more electron
shells as you go down the group. In the metallic lattice, the nuclei of the positive ions are
further from the delocalised electrons as the elements period number increases therefore
there is a weaker electrostatic force of attraction so less energy is required to mechanically
break apart the metal lattice.
6.3 Describe the reactions of lithium, sodium and potassium with water
> All of the group 1 metals react with water in the same way: they all produce a metal
hydroxide and hydrogen:
> The important difference between the reactions of different alkali metals is how quickly
they happen. As you go down the group more rapidly the reaction occurs, due to increased
reactivity.
Lithium:
,The reaction of lithium with water is very similar to that of sodium however this reaction is
slower. The melting point of lithium is higher than that of sodium so therefore lithium doesn't
melt as quickly,
Sodium:
Sodium floats as it’s less dense than the water surrounding water, it then melts into a ball
due to its low melting point which is surpassed by the heat produced by the reaction. There
is” effervescing” or fizzing due to hydrogen gas production. The sodium will travel around on
top of the water’s surface due to the hydrogen not being symmetrically given off around the
ball. Finally the sodium eventually disappears as it is used up throughout the reaction.
Potassium:
In comparison to sodium, the reaction of potassium with water takes place at an increased
rate. Enough heat is produced to actually ignite the hydrogen resulting in it burning with a
lilac flame. The reaction ends with the potassium acting explosively and spitting.
6.4 Describe the pattern in reactivity of the alkali metals, lithium, sodium and
potassium, with water; and use this pattern to predict the reactivity of other alkali
metals
The pattern: Metals become more reactive the further down the group you travel.
> Therefore, rubidium and caesium can be predicted to react even more violently than
potassium yet still produce the corresponding metal hydroxide ie rubidium hydroxide and
caesium hydroxide.
6.5 Explain this pattern in reactivity in terms of electronic configurations
As you go down the group, it is easier to lose electrons and form positive ions (cations) due
to the increasing number of electron shells as you go down the group. This means there is a
larger distance between the positively charged nucleus, so the attraction is weaker. As more
shells come, the weaker the attraction, therefore easier to lose the electrons. The reactivity
of a metal is determined by how easily it loses its electrons.
, Group 7
6.6 Recall the colours and physical states of chlorine, bromine and iodine at room
temperature
6.7 Describe the pattern in the physical properties of the halogens, chlorine, bromine
and iodine, and use this pattern to predict the physical properties of other halogens
> There is a trend in state from gas to liquid to solid down the group. This is because the
melting and boiling points increase as you go down the group due to increasing
intermolecular forces as the atoms become larger due to increasing proton and electron
numbers etc, so more energy is needed to overcome these forces as they are stronger.
> From this, any halogen above chlorine will be gases (their boiling points lower) and any
below iodine will be solids (their melting points even higher).
> The colour of the halogens gets darker as you go down the group.
6.8 Describe the chemical test for chlorine
When a damp litmus paper is put into chlorine gas, the litmus paper is bleached and turns
white. The litmus paper may turn red briefly before turning white because acids are
produced when chlorine comes into contact with water and quickly forms HCl acid which is
red in litmus paper but then gets neutralised.
6.9 Describe the reactions of the halogens, chlorine, bromine and iodine, with metals
to form metal halides, and use this pattern to predict the reactions of other halogens
Halogen + metal -> metal halide
> Halogens react with metals to form ionic compounds in which the halide ion carries a –1
charge because it gains one electron that it is donated to by the metal.
> Reactivity decreases down the group so the reaction is less vigorous as you move down
group 7, but they still all react to form metal halides.
6.10 Recall that the halogens, chlorine, bromine and iodine, form hydrogen halides
which dissolve in water to form acidic solutions, and use this pattern to predict the
reactions of other halogens
Halogen + Hydrogen -> hydrogen halide
> The halogens react with hydrogen to form hydrogen halides ie hydrogen chloride,
hydrogen bromide and hydrogen iodide. Hydrogen halides are all poisonous, acidic gases
and they are covalently bonded. In addition, they are very soluble in water, reacting with it to
produce acid solutions.
> Reactivity decreases down the group, so iodine reacts less vigorously with hydrogen than
chlorine (which requires light or high temp to react with hydrogen). Fluorine is the most
reactive (reacts with hydrogen at low temperatures in the absence of light).
> Therefore any halogen underneath iodine will have less vigorous reactions with hydrogen
6.11 Describe the relative reactivity of the halogens chlorine, bromine and iodine, as
shown by their displacement reactions with halide ions in aqueous solution and use
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