Cambridge​ ​IGCSE​ ​Chemistry
Topic​ ​9:​ ​The​ ​Periodic​ ​Table
Noble​ ​gases
Notes
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Describe​ ​the​ ​noble​ ​gases,​ ​in​ ​Group​ ​VIII​ ​or​ ​0,​ ​as​ ​being…
● Unreactive,​ ​monatomic​ ​gases​ ​(exist​ ​as​ ​He​ ​rather
than​ ​He​2​)
● They​ ​have​ ​8​ ​electrons​ ​in​ ​their​ ​outer​ ​shell​ ​(except
helium,​ ​which​ ​has​ ​2).
● They​ ​are​ ​unreactive​ ​and​ ​do​ ​not​ ​easily​ ​form
molecules,​ ​because​ ​they​ ​have​ ​full​ ​outer​ ​shells,
meaning​ ​they​ ​have​ ​a​ ​stable​ ​arrangement​ ​of
electrons.
State​ ​the​ ​uses​ ​of​ ​the​ ​noble​ ​gases​ ​in​ ​providing​ ​an​ ​inert​ ​atmosphere,​ ​i.e.
argon​ ​in​ ​lamps,​ ​helium​ ​for​ ​filling​ ​balloons
● Helium-​ ​filling​ ​balloons:​ ​less​ ​dense​ ​than​ ​air​ ​so​ ​the​ ​balloons​ ​float​ ​and​ ​He​ ​is
non-flammable
● Neon​ ​–​ ​advertising​ ​signs
● argon/krypton/xenon-​ ​gas​ ​in​ ​filament​ ​lamps:​ ​inert
● argon-​ ​shielding​ ​gas​ ​in​ ​welding:​ ​denser​ ​than​ ​air​ ​so​ ​keeps​ ​air​ ​off​ ​of​ ​metal​ ​and
inert​ ​so​ ​metal​ ​won’t​ ​oxidise
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Cambridge​ ​IGCSE​ ​Chemistry
Topic​ ​9:​ ​The​ ​Periodic​ ​Table
Transition​ ​elements
Notes
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Describe​ ​the​ ​transition​ ​elements​ ​as…
● A​ ​collection​ ​of​ ​metals​ ​having​ ​high​ ​densities,​ ​high​ ​melting​ ​points​ ​and​ ​forming
coloured​ ​compounds,​ ​and​ ​which,​ ​as​ ​elements​ ​and​ ​compounds,​ ​often​ ​act​ ​as
catalysts
(Extended​ ​only)​ ​Know​ ​that​ ​transition​ ​elements​ ​have​ ​variable​ ​oxidation
states
● Transition​ ​elements​ ​have​ ​variable​ ​oxidation​ ​states,​ ​meaning​ ​they​ ​can​ ​form​ ​ions
with​ ​different​ ​charges
o E.g.​ ​Cu​+​​ ​or​ ​Cu​2+
● the​ ​oxidation​ ​state​ ​a​ ​transition​ ​metal​ ​is​ ​in​ ​is​ ​often​ ​shown​ ​using​ ​roman​ ​numerals
e.g.​ ​iron​ ​(II)​ ​=​ ​Fe​2+​​ ​and​ ​iron​ ​(III)​ ​=​ ​Fe​3+
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Cambridge​ ​IGCSE​ ​Chemistry
Topic​ ​9:​ ​The​ ​Periodic​ ​Table
Group​ ​properties
Notes
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Describe​ ​lithium,​ ​sodium​ ​and​ ​potassium​ ​in​ ​Group​ ​I​ ​as…
●
A​ ​collection​ ​of​ ​relatively​ ​soft​ ​metals​ ​showing​ ​a​ ​trend​ ​in​ ​melting​ ​point,​ ​density
and​ ​reaction​ ​with​ ​water
(Extended​ ​only)​ ​Identify​ ​trends​ ​in​ ​Groups,​ ​given​ ​information​ ​about​ ​the
elements​ ​concerned
● Similar​ ​chemical​ ​properties​ ​due​ ​to​ ​the​ ​fact​ ​that​ ​they​ ​have​ ​the​ ​same​ ​number​ ​of
outer​ ​shell​ ​electrons
● Once​ ​you​ ​are​ ​given​ ​information​ ​regarding​ ​more​ ​than​ ​one​ ​element​ ​in​ ​a​ ​group,
look​ ​at​ ​each​ ​of​ ​their​ ​positions​ ​in​ ​the​ ​group​ ​(i.e.​ ​near​ ​the​ ​top​ ​or​ ​bottom)​ ​and
identify​ ​the​ ​trend​ ​shown​ ​by​ ​the​ ​elements​ ​with​ ​given​ ​information​ ​(e.g.​ ​reactivity
or​ ​boiling​ ​point​ ​could​ ​increase​ ​down​ ​the​ ​group)
o Going​ ​down​ ​a​ ​group​ ​means​ ​going​ ​up​ ​in​ ​number​ ​of​ ​electron​ ​shells,​ ​more
electron​ ​shielding​ ​and​ ​so​ ​less​ ​attraction​ ​between​ ​the​ ​nucleus​ ​and​ ​outer
shell​ ​electrons
Predict​ ​the​ ​properties​ ​of​ ​other​ ​elements​ ​in​ ​Group​ ​I,​ ​given​ ​data,​ ​where
appropriate
● Melting​ ​point
o Low​ ​melting​ ​points​ ​compared​ ​to​ ​most​ ​other​ ​metals
▪ As​ ​you​ ​go​ ​down​ ​the​ ​group,​ ​melting​ ​points​ ​decrease
● Density
o Low​ ​densities​ ​–​ ​they​ ​will​ ​float​ ​on​ ​water
▪ As​ ​you​ ​go​ ​down​ ​the​ ​group,​ ​densities​ ​increase
● Reaction​ ​with​ ​water
o All​ ​react​ ​vigorously​ ​with​ ​water​ ​to​ ​create​ ​an​ ​alkaline​ ​solution​ ​and
hydrogen​ ​(i.e.​ ​you​ ​will​ ​see​ ​bubbling/effervescing​ ​due​ ​to​ ​the​ ​production​ ​of
a​ ​gas)
o More​ ​bubbles​ ​with​ ​reaction​ ​with​ ​water​ ​=​ ​more​ ​vigorous​ ​reaction​ ​=​ ​more
reactive​ ​alkali​ ​metal​ ​(Group​ ​I​ ​metal)
▪ Reactivity​ ​increases​ ​down​ ​the​ ​group​ ​(so​ ​reaction​ ​becomes​ ​more
vigorous)
▪ Down​ ​the​ ​group​ ​–​ ​easier​ ​to​ ​lose​ ​electrons​ ​and​ ​form​ ​positive​ ​metal
ions​ ​(cations),​ ​these​ ​are​ ​formed​ ​when​ ​metals​ ​react
▪ It​ ​is​ ​easier​ ​to​ ​lose​ ​electrons​ ​due​ ​to​ ​the​ ​increase​ ​in​ ​electron​ ​shells
and​ ​therefore​ ​there​ ​is​ ​more​ ​electron​ ​shielding​ ​and​ ​easier​ ​to​ ​lose
electrons​ ​due​ ​to​ ​the​ ​decrease​ ​in​ ​attraction​ ​between​ ​the​ ​positively
charged​ ​nucleus​ ​and​ ​the​ ​negatively​ ​charged​ ​outer​ ​shell​ ​electrons
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Describe​ ​the​ ​halogens,​ ​chlorine,​ ​bromine​ ​and​ ​iodine​ ​in​ ​Group​ ​VII,​ ​as…
●
A​ ​collection​ ​of​ ​diatomic​ ​non-metals​ ​showing​ ​a​ ​trend​ ​in​ ​colour​ ​and​ ​density
…​ ​and​ ​state​ ​their​ ​reaction​ ​with​ ​other​ ​halide​ ​ions
● reactivity​ ​decreases​ ​going​ ​down​ ​the​ ​group:
○ outer​ ​shell​ ​becomes​ ​further​ ​from​ ​nucleus​ ​and​ ​there​ ​is​ ​more​ ​shielding
from​ ​inner​ ​electrons
○ attraction​ ​between​ ​nucleus​ ​and​ ​outer​ ​electrons​ ​decreases
○ electrons​ ​are​ ​gained​ ​less​ ​easily​ ​(which​ ​is​ ​how​ ​halogens​ ​react)
● a​ ​more​ ​reactive​ ​halogen​ ​will​ ​displace​ ​halide​ ​ions​ ​of​ ​a​ ​less​ ​reactive​ ​halogen
● chlorine​ ​will​ ​displace​ ​both​ ​bromide​ ​and​ ​iodide​ ​ions:
○ chlorine​ ​+​ ​sodium​ ​bromide​ ​→​ ​sodium​ ​chloride​ ​+​ ​bromine
○ chlorine​ ​+​ ​sodium​ ​iodide​ ​→​ ​sodium​ ​chloride​ ​+​ ​iodine
● bromine​ ​will​ ​displace​ ​iodide​ ​but​ ​not​ ​chloride​ ​ions
○ bromine​ ​+​ ​potassium​ ​iodide​ ​→​ ​potassium​ ​bromide
● iodine​ ​will​ ​not​ ​displace​ ​chloride​ ​or​ ​bromide​ ​ions
Predict​ ​the​ ​properties​ ​of​ ​other​ ​elements​ ​in​ ​Group​ ​VII,​ ​given​ ​data​ ​where
appropriate
● Colour
o Darker​ ​in​ ​colour​ ​as​ ​you​ ​go​ ​down​ ​the​ ​group
▪ Fluorine​ ​is​ ​very​ ​pale​ ​yellow
▪ Chlorine​ ​is​ ​yellow-green
▪ Bromine​ ​is​ ​red-brown
▪ Iodine​ ​is​ ​purple
● Density
o Density​ ​increases​ ​as​ ​you​ ​go​ ​down​ ​the​ ​group
▪ Chlorine​ ​is​ ​a​ ​gas
▪ Bromine​ ​is​ ​a​ ​liquid
▪ Iodine​ ​is​ ​a​ ​solid
● reactivity
o decreases​ ​down​ ​the​ ​group
o outer​ ​shell​ ​becomes​ ​further​ ​from​ ​nucleus​ ​and​ ​there​ ​is​ ​more​ ​shielding
from​ ​inner​ ​electrons,​ ​attraction​ ​between​ ​nucleus​ ​and​ ​outer​ ​electrons
decreases,​ ​electrons​ ​are​ ​gained​ ​less​ ​easily​ ​(which​ ​is​ ​how​ ​halogens​ ​react)
o A​ ​more​ ​reactive​ ​halogen​ ​can​ ​displace​ ​a​ ​less​ ​reactive​ ​one​ ​in​ ​an​ ​aqueous
solution​ ​of​ ​its​ ​salt
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Cambridge​ ​IGCSE​ ​Chemistry
Topic​ ​9:​ ​The​ ​Periodic​ ​Table
Periodic​ ​trends
Notes
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Describe​ ​the​ ​change​ ​from​ ​metallic​ ​to​ ​non-metallic​ ​character​ ​across​ ​a​ ​period
● From​ ​left​ ​to​ ​right​ ​elements​ ​change​ ​from​ ​metallic​ ​to​ ​non-metallic​ ​character
● Metallic​ ​character/properties:
o Shiny
o Conductive
o Dense
o Malleable
● On​ ​either​ ​side​ ​of​ ​the​ ​red​ ​line,​ ​you​ ​have​ ​some​ ​elements​ ​known​ ​as​ ​“metalloids”
that​ ​have​ ​both​ ​metallic​ ​and​ ​nonmetallic​ ​properties,​ ​such​ ​as​ ​silicon​ ​(which​ ​forms
silicon​ ​dioxide…)
(Extended​ ​only)​ ​Describe​ ​and​ ​explain​ ​the​ ​relationship​ ​between​ ​Group
number,​ ​number​ ​of​ ​outer​ ​shell​ ​electrons​ ​and​ ​metallic/non-metallic
character
● Group​ ​number-​ ​shows​ ​the​ ​number​ ​of​ ​electrons​ ​in​ ​the​ ​outer​ ​shell
● Metallic​ /​ nonmetallic-​ ​metals​ ​form​ ​positive​ ​ions​ ​by​ ​losing​ ​electrons​ ​and
nonmetals​ ​form​ ​negative​ ​ions​ ​by​ ​gaining​ ​electrons.​ ​All​ ​of​ ​group​ ​1​ ​and​ ​2​ ​are
metals,​ ​all​ ​of​ ​group​ ​7​ ​and​ ​8​ ​(0)​ ​are​ ​nonmetals.​ ​In​ ​groups​ ​3,4,5,6​ ​there​ ​is​ ​a
transition​ ​between​ ​metals​ ​and​ ​nonmetals.
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Cambridge​ ​IGCSE​ ​Chemistry
Topic​ ​9:​ ​The​ ​Periodic​ ​Table
The​ ​Periodic​ ​Table
Notes
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Describe​ ​the​ ​Periodic​ ​Table​ ​as​ ​a​ ​method​ ​of​ ​classifying​ ​elements​ ​and​ ​its​ ​use
to​ ​predict​ ​properties​ ​of​ ​elements
● The​ ​Periodic​ ​Table​ ​can​ ​be​ ​used​ ​to​ ​classify​ ​elements​ ​and​ ​predict​ ​properties​ ​of
elements​ ​by​ ​the​ ​way​ ​that​ ​they​ ​are​ ​arranged​ ​in​ ​the​ ​table…
o Elements​ ​are​ ​arranged​ ​in​ ​order​ ​of​ ​atomic​ ​(proton)​ ​number​ ​(bottom
number)​ ​and​ ​so​ ​that​ ​elements​ ​with​ ​similar​ ​properties​ ​are​ ​in​ ​columns,
known​ ​as​ ​groups.
o Elements​ ​in​ ​the​ ​same​ ​periodic​ ​group​ ​have​ ​the​ ​same​ ​amount​ ​of​ ​electrons
in​ ​their​ ​outer​ ​shell,​ ​which​ ​gives​ ​them​ ​similar​ ​chemical​ ​properties.
● You​ ​can​ ​deduce​ ​the​ ​electronic​ ​configurations​ ​of​ ​elements​ ​from​ ​their​ ​positions​ ​in
the​ ​Periodic​ ​Table
o Group​ ​1​ ​has​ ​1​ ​electron​ ​in​ ​its​ ​outer​ ​shell,​ ​group​ ​2​ ​has​ ​2​ ​etc…
o Period​ ​1​ ​has​ ​1​ ​shell,​ ​period​ ​2​ ​has​ ​2​ ​shells​ ​etc…
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