Alkali Group 2 Metals and halogens Flashcards Preview

A Level Chemistry Inorganic > Alkali Group 2 Metals and halogens > Flashcards

Flashcards in Alkali Group 2 Metals and halogens Deck (38)
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What is the trend in group 2 metals going down the periodic table in atomic size

The atomic size increases as going down group 2 as the number of outer shells increases


What is the trend for in first ionisations energy in group 2 elements going down the group

First ionisation energy decreases going down group 2 as the outer shells are more shielded from the nucleus by the inner electrons so they are held less closely and so are easier to remove


What is the trend in electronegativity going down group 2

Electronegativity decreases as the outer shells are shielded from the nucleus and so the attraction reduced


State the trend in melting points of elements going down group 2

The melting points of the elements decrease going down group 2 as the attraction between the cations and delocalised electrons decreases due to atom getting bigger


What is produced when MG reacts with steam and give the equation

Mg+2H20->Mg(oh )+H2

It reacts with steam


Give the equations for when strontium and barium react with cold water




State the trend in solubitly of sulphates in group 2 and give the most soluble and insouble

Solubility of sulphates decreases going down group 2

I.e. Ba(+2) + SO4-BaSO4

MgSO4 is soluble and SrSO4 and BaSO4 are insoluble


What two alkali metals don't react with water and which one react with steam

Be and Mg

Mg reacts with steam


What is produced when Ba reacts with sulphate ions

Thick white precipitate (barium meal)


How would u test for sulphate ions

Add barium chloride,dilute HCL and the unknown solution

If a white precipitate forms sulphate ions are present


When testing for sulphate ions why is HCL added

To remove other ions like hydroxide ions and carbonate ions as they may affect the test


State the solubility of hydroxides in group 2

Solubility increases going down group 2

Mg+2 OH->MgO+ H2



What can magnesium hydroxide be used for

As it's almost insouble it's used in milk of magnesia for indigestion


What is calcium hydroxide used for

In slaked lime in order to neutralise acidic soil


What is barium sulphate used for

It's used in a barium meal in the gut where it can absorb x rays and it's completely insouble


Give the order of electronegativity in group 7 from highest to lowest



Give the order of the strongest oxidising agents in group 7



Why does oxidising power increase going group 7

As their are fewer number of shells in the atom,so electrons are closer to the nucleus and are less shielded,this means the attraction of electrons to the nucleus is stronger and so the atom is more likely to accept electrons


State the trend in reducing power going down group 7 and why

Reducing power increases with iodine being the strongest reducing agent as the atom gets larger so the outer electrons are further away from the nucleus and so less attracted


What is meant by displacement reactions

This is when halogens that are the strongest oxidising agent wil displace more reactive halides(reducing agents)


What happens when chlorine displaces both bromine and iodine and give the equations

CL2 +2Br- ->2CL- +Br2 and orange colour will appear

CL2 +2I->2Cl- +I2
And a brown colour will appear


What happens when bromine displaces iodine

Br2+2I-->2Br- +I2

A brown colour will appear


What is seen when Cl is reacted with H2SO4 and state the type of reaction it is

White fumes of HCL are produced

The fumes will turn blue litmus paper red

Acid base reaction


What is produced with Bromine reacts with H2SO4 and state what happens to the sulphuric acid

Red colour of bromine
White fumes that can turn litmus paper red
HBR is made

Sulphuric acid is reduced to sulphur dioxide +6 to +4

Bromine Increases from -1 to 0


What is produced when iodine reacts with H2SO4 and state what happens to the sulfur

White fumes that will turn blue litmus paper red

Purple colour or iodine

Smell of rotten eggs due to H2S

Sulfur reduced from +6 to -2

H2SO4 reduced to H2S


In reactions with the halides what does the concentrated sulphuric acid behave as

An oxidising agent


When reacted with sliver ions and nitric acid state the precipitates formed when reacted with halide ions

Chlorine will produce a white precipitate

Bromine a cream precipitate

Iodine a yellow precipitate

AgNo3 +Br- -> AgBr


Why is nitric acid added

To ensure that an hydroxide ions or impurities are removed


State how we can distinguish between the precipitate that halide ions form and give the reactions with each halide ion

We add ammonia

If dilute or conc ammonia is added to AgCl the precipitate will dissolve

If conc ammonia is added to Agbr the precipitate is soluble

AgI is insouble in conc ammonia


Give the equation when chlorine reacts with water and state the type of reaction it is

CL2 +H20->HCL +HClo

It's disproportionation as the chlorine is simultaneously oxidised and reduced