Summary Want a 300/300? These are Chemistry As Paper 2: Energetics, Group Chemistry, Halogenoalkanes and Alcohols from a student who got a 300/300

Un ↑
:

-1--2
G•&




Revision

, To help distinguish
state water hexane
Physical
→ Fz Pale yellow
-
-


refrigerants
Green Pale pale green PVC /Polymers
ccz -

yellow gas green

Brz red -


Orange orange-brown orange disinfect water

Iz Grey Solid Brown purple disinfect water
( sublimes to purple )

→ ALF} ionic d- LLL } /ALZCCG Covalent
,




numbers
→
They have variable oxidation as e- in
p sub shells can be promoted to I sub shells
energy

compensated bonds formed
is
by new




Atomic radius down the while decreases
→ increases
group electronegativity
•
More shells

•
More
shielding
•

bigger atomic radius
As despite nuclear charge attracted
outer shell is less
strongly
•




First the released
affinity of
→ e- is
energy when I mole of e- is squired by 1 mole
gaseous
atoms form 1 ions ith 1-
to role of
gaseous charge
-
a




exothermic Stig,
-




xig,
'




keg ) t e → x 1- e- →


> endothermic as there is repulsion
down -1L
→ e-
affinity decreases group as atom gets bigger
so shell held less bond formed less
energy released
outer e-
strongly
is so weaker so




has high
→
Fz has lower e-
affinity as
it a
negative charge density so the incoming
e-


experiences repulsion thus forming a weaker attraction with th nucleus so less is released
energy

the BP the and have thus
going down
→
group MP and
get bigger
increases as atoms more e-


forming stronger london forces and hence is needed to break them
energy
more




11-20 1- Clz → HCL t HOCL
It Br HOA
>
disproportionation HI HOI
} lesser extent then "
2




Iz Soluble KI it forms Is
_

→ in as which are brown


> dissolves hexane both form london forces which forces
they
london
compensates for
-




more in as


broken ( while less soluble in H2O as i 't forms It bonds )
-
.

, Bond enthalpies decreases down the as atoms set
bigger and the bond
group covalent
→ weaker

as its longer


→ Fz is an
exception as the small atom size leads to them being too close to each other

so the outer shell electrons exert repulsion and so it bond is weaker (despite the bond being shorter ) .




→ It-3L bond
enthalpy decreases down the group as x
gets bigger so the bond is longer and

the nucleus of is further from the bonded pair so it experiences weaker attraction Thus
away
× a .




the bond is weaker Exception It -
F It -
bonds .




,
.




→ when Brz is added to KI I is
displaced to Iz So the solution darkens from
,


red-orange to brown



down group halogens get bigger nucleus attract less
→
reactivity decreases an
so
easily
-



as can e .




there the atomic radius is
bigger due thus despite nuclear
as are more shells so to more
shielding change it


attracted
e- are less
strongly

→ Halogens are weaker
oxidising agents down the
group
as its more difficult for them to
gain
e-




→
Fz is too
strong Of an
oxidising agent to be used in displacement reaction as if oxidises water

Fzt Hzo ZHF
{
> t
Oz




→ xzt It , → ICH
the ✗ It forms less Iz doesn't this
↳ down
group explosively where even react
fully with constant
heating : _




shows
reactivity

when rates of x with P we need to be careful Brz liquid so more contant
comparing as is
• a



then Clz which is a gas thus rate is affected


•
Clzt PCL } → PCLS


ZP Biz
}
• t 3 → 2PBʳ
} Oxdisi > e
@
weaker oxidising agents so
they P till 1- 3
ZP t 3 Iz → ZPI}


t Clz 2cL
-
-


Ze - > xs
2- Nak KOH tch 2403-+6720 the
-
-



•
2N at Xz > → white Sol ;D
-
>

>
orange flense
-




Feliu ) halide

2Fe t 3Fz > ZFEF} ( white solid ,
with cold irons
if 1120
2Fe t 3 ccz > ZFECL } ( black solid red '- brown colour ) hot iron
,


2 Fet 3 Brz > 2 Fe Br
}
( red -
brown solid ) hot iron but rate is slower


Fet Iz > Fetz } Few ) halide as weaker oxidising agent