topic 6 Groups in the periodic table Flashcards
Why are some metals in certain groups as others
they have the same number of electons in their outer most shell
group 1 alkali metals are
soft
low melting and boiling point
why are group metals very reactive
group 1 readily lose their single outer electron
The more readily a metal loses its electron the more reactive.
As you go down more reactive as outer shell is further from nucleus so more ready
reaction of lithium in water
lithium will move around the surface , fizzing furiously
reaction of sodium in water
moves around surface faster and fizzes more furiously than sodium as well as melt in the heat of reaction
reaction of potassium in water
moves along surface fastest and fizzes the most as well as ignites the hydrogen gas produced
trends in reaction of Lithium, sodium and potassium in water
produces hydrogen gas and a hydroxide of the metal
Reaction increases down the group. The reaction is stronger as the outer electron is further from the nucleus
group 7
what state and colour is chlorine at room temp.
Green gass- poissonous, fairly reactive
what state and colour is Bromine at room temp.
red-brown liquid gives of orange vapour
what state and colour is Iodine at room temp.
dark grey crystaline solid that gives of a purple vapour when heated
Patterns in group 7
As you go down the melting points and boiling points of the halogens INCEASE
predict elements further down the table
gets darker down the table and becomes more solid as well as melting point increasing
chemical test for chlorine
Use DAMP BLUE LITMUS PAPER.
hold a piece of the paper over it.
chlorine will bleach it white
describe ractivity trend of group 7
As you go down the halogens get less reactive- It gets harder to attract the extra electron to fill the outer shell when its further from the nucleus
Halogens reaction with metals
halogens react vigourously with some metaks to form salts called ‘metal halides’
Halogens higher up are more reactive.
2Na + Cl2 = 2NaCl
Halogen reaction with hydrogen
Halogens react with hydrogen to form hydrogen halides ( they are soluble and dissolve in waterto form acidic solutions).
H2+Cl2=2HCl
Halogen displacement reaction
Displacement reaction where more reactive element displaces a less reactive element.
Why is displacement a redox reaction
The halogen displacement reaction is redox (oilrig) as The halogen gains elctrons while halide ions lose electrons.
Chlorine is reduced to chlorine ions, so the salt solution becomes potassium chloride. Bromide ions are oxidised to bromine which turns the solution orange
Displacement reaction within group to find reactivity
1) add small amount of halide salt solution in a test tube
2) add few drops of halogen solution and shake gently
3) if a colour change occurs then reaction taken place.
4)repeat process using different combinations
results:
chlorine displaces both bromine and iodine from salt solutions
Bromine can’t displace chlorine but does displace iodine. Iodine can’t displace anything
Group 0 noble gasses
properties of Noble gasses
colourless at room temp
monatomic (made up of sinfle atoms)
Full outer shell so inert and son’t give up or gain elctron easily
non-flammabel
Uses of Noble gasses
Depends on their inertness, flammability/ non-flammability
Argon used in filament lamps as non-flamable stops filaments from burning away
argon and helium used to protect metals while weilding.
Helium used in airships
trend in properties
boiling point, melting point and density all INCREASE as you go DOWN Group 0
