The Periodic Table

Question 1

the Periodic Table as a method of classifying elements and its use to predict properties of elements

Answer 1

o Elements​ ​are​ ​arranged​ ​in​ ​order​ ​of​ ​atomic​ ​(proton)​ ​number​ ​(bottom number)​ ​and​ ​so​ ​that​ ​elements​ ​with​ ​similar​ ​properties​ ​are​ ​in​ ​columns (groups)
o Elements​ ​in​ ​the​ ​same​ ​periodic​ ​group​ ​have​ ​the​ ​same​ ​amount​ ​of​ ​electrons in​ ​their​ ​outer​ ​shell,​ ​which​ ​gives​ ​them​ ​similar​ ​chemical​ ​properties.
o Group​ ​1​ ​has​ ​1​ ​electron​ ​in​ ​its​ ​outer​ ​shell,​ ​group​ ​2​ ​has​ 2 in its outer shell etc…

Question 2

change from metallic to non- metallic character across a period

Answer 2

From​ ​left​ ​to​ ​right​ ​elements​ ​change​ ​from​ ​metallic​ ​to​ ​non-metallic​ ​character
● Metallic​ ​character/properties:
o Shiny
o Conductive 
o Dense
o Malleable

Question 3

relationship between group number, number of outer-shell electrons and metallic/non-metallic character

Answer 3

● 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.

Question 4

lithium, sodium and potassium in Group I

Answer 4

a collection of relatively soft metals showing a trend in melting point, density and reaction with water

Question 5

Identify trends in groups

Answer 5

● Similar​ ​chemical​ ​properties​ ​due​ ​to​ ​the​ ​same​ ​number​ ​of outer​ ​shell​ ​electrons
● 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

Question 6

Predict the properties of other elements in Group I

Answer 6

● 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

Question 7

halogens, chlorine, bromine and iodine in Group VII

Answer 7

a collection of diatomic non-metals showing a trend in colour and density and state their reaction with other halide ions

Question 8

their reaction with other halide ions

Answer 8

● 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

Question 9

properties of other elements in Group VII

Answer 9

● 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

Question 10

Transition elements

Answer 10

a collection of metals having high densities, high melting points and forming coloured compounds, and which, as elements and compounds, often act as catalysts

Question 11

transition elements have variable oxidation states

Answer 11

● Transition​ ​elements​ ​have​ ​variable​ ​oxidation​ ​states,​ ​meaning​ ​they​ ​can​ ​form​ ​ions with​ ​different​ ​charges
o E.g.​​Cu+​​​​or​​Cu2​+

Question 12

Noble gases, in Group VIII or 0

Answer 12

● 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.

Question 13

uses of the noble gases

Answer 13

● 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