Topic 6 Flashcards
what are the properties of group 1 metals
- low mp and bp
- soft
- one outer shell electron
- alkali metals
- form ionic compounds because easily lose electron so don’t need to form covalent
- more reactive as down group because less electron shielding so weaker force of attraction between positive nucleus and negative electron so it loses it easier
what happens when you react alkali metals with gold water
- produces a hydroxide and hydrogen gas
- reactivity increases down group so results more violent
- lithium move around surface fizzing furiously
- sodium and potassium do same but melt and potassium produces a lilac flame
- rubidium and ceasium explode
what are the properties of group 7 halogens
- 7 electrons in outer shell
- exist as diatomic molecules sharing one pair of electrons in a covalent bond giving both atoms full outer shell
- as you go down mp and bp increases
- as you go down reactivity decreases because there is more shielding so a weaker force of attraction between nucleus and electron it wants to gain, larger atomic radius
what are the colours and state of group 76 halogens at room temperature
- chlorine is a green gas
- bromine is a red-brown liquid
- iodine is a dark grey solid which is a purple vapour when heated
test for chlorine
damp blue litmus red then bleach white
how will a halogen react with a salt
to form a metal halide
sodium + chlorine -> sodium chloride
how will a halogen react with hydrogen
to form a hydrogen halide
- hydrogen halides are soluble in water and disolve to from an acidic solution
discuss halogen displacement
- halogen displacement reactions are redox reactions. halogens gain electrons (reduction) whilst halides lose electrons (oxidation)
- for example chlorine is more reactive than bromine so if you add chlorine water (an aqueous solution of C2) to potassium bromide solution. The chlorine will displace the bromine from the salt solution
- chlorine reduced to chlorine ions so salt solution becomes pottasium chloride
- bromide ions oxidised to bromine turning solution orange
what are the properties of group 0 the noble gases
- colourless gases at room temperature
- monatomic meaning their gases are made up of single atoms not molecules
- more or less inert (unreactive) because they have a full outer shell so don’t easily give up or gain electrons
- as inert they are non-flammable
why did it take a long time for the noble gases to be discovered
because their properties are hard to observe
discuss the uses of the noble gases
- used to provide an inert atmosphere
- argon is used in filament lamps because its non-flammable it stops the very hit filament burning away
- flash photography uses the same principle. Argon, Krypton and Xenon are used to stop the flash filament from burning up during the high temperature flashes
- argon and helium are used to protect metals that are been welded as the inert atmosphere stops the hot metal reacting with oxygen
- helium is used in airships and party balloons. Helium has a lower density than air so it does make balloons float. It is also non-flammable making it safer to use than hydrogen gas
what are the trends in the properties of the noble gases
- bp, mp and density increase as you go down group 0
