The Oxides of Period 3 Elements Flashcards
Give the equation when oxygen reacts with sodium,magnesium and aluminium and state what type of oxides are formed
4Na+O2->2Na2O ionic oxide
2Mg+O2->2Mgo ionic oxide
4Al+3O2->2Al2O3 mostly ionic/covalent
Give the equations when phosphorus,sulphur and silicon react with oxygen
Si+O2->SiO2
S+O2->SO2
P4+5O2->P4O10
Molecular covalent oxides are produced
Why is melting point of the oxides high and why do magnesium and aluminium oxide have a higher melting point than sodium oxide
They are ionic so they contain electrostatic forces of attraction and aluminium and magnesium have a higher charge than sodium
Despite being covalent why does silicon dioxide have a high melting point
They have a giant covalent structure and their are a lot of strong covalent bonds between the atoms in which a lot of energy is need to break
Why is the melting points for p4O10 and So3 low
As they are molecular covalent and the only intermolecular forces that exist between them are van der waals
Why is the melting point of P4O10 higher than So3
As it’s a larger molecule and so it has stronger van der waals forces
What happens when ionic oxides react with water and what does it mean
They produce hydroxide ions and so they act as bases they have o2- ions
What happens when covalent oxides react with water
They release H+ ions as well as producing a hydroxide and so are acidic
What it meant by amphoteric
That the compound can behave as either an acid or base
Give the equations for the reactions with sodium with water and acids and give the Ph when it reacts with water
(Same with mgo)
Na2O +H2O->2NaOH
Na2O+2H+->2Na+. H20
Ph 14
Give the ph when Mgo reacts with water
Ph is 9
What type of oxide is aluminium and what does it mean and state why it doesn’t dissolve in water and give the ph and equations
It’s an amphoteric oxide and it’s insoluble in water meaningful dissolves in both acid and alkalis
Al2O3 +6HCL->2AlXl
Why can’t silicon oxide react with water,state what it can react with and give the ph
Ph=7
It’s insoluble in water it dissolves in hot concentrated alkalis
SiO2 +2OH-> SIO3(2-) +H20
What type of oxide is phosphorus oxide and state what it reacts with as well as giving the ph and equations
P4O10 +6H20-> 4H3PO4
Ph= 3
P4O10+12OH- ->4PO4 (-3) +6H20
Give the equations when So2 and So3 react with water and alkalis and give the ph
So2 +H20->H2SO3 ph= 2
So3 +h20 ->H2SO4 ph=1
So2+ 2OH- -> SO3(2-)+H2O
So+2OH- -> SO4 (2-)