Periodicity of period 3

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  • Created by: Hindleyc
  • Created on: 16-04-19 17:30
What does sodium react with
cold water
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how
fizzes around on surface
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EQN
2Na (s) + 2H2O (l)= 2NaOH (aq) + H2(g)
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How does Magnesium react with cold water, to form
very slowly , the hydroxide
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What does it react more readily with, to form
Steam to form the oxide
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eqn
Mg(s) +H2O(g)= MgO(s)+H2(g)
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What do the elements (Na.Mg,Al,Si,P, and S) react with to form
oxygen to form oxides
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What does sodium burn with to produce
yellow flame, white solid
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What does Mg, Al, Si and P burn with to give
white flame to give white solid ,smoke ?
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What does S burn with to form
Blue flame to form an acidic choking gas
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What is Sodium and phosphorus stored under ,why
oil, water to stop these elements coming into contact and reacting with air
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Sodium reaction with oxygen
4Na(s)+O2(g)=2Na2O(s)
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Magnesium reaction with oxygen
2Mg(s) + O2(g)=2MgO(s)
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Aluminium reaction with oxygen
4Al+3O2(g)=2Al2O3 (s)
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Silicon reaction with oxygen
Si +O2(g)=SiO2(s)
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Phosphorus reaction with oxygen
4P +5O2(g)=P4O10(s)
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Sulfur reaction with oxygen
S+ O2(g)=SO2(g)
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What are the metal oxides Na2O, MgO, Al2O3
ionic oxides
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What do they have
High melting point
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Why type of structures
Ionic giant lattice
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what do they therefore have and what does this mean
strong forces of attraction between ions therefore high melting point
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Why is it ionic
Because of the large electronegativity difference between metal and oxygen
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What does increasing charge on the cation make the ionic forces
stronger (bigger lattice enthalpies of dissociation) going from Na to Al so leading to increasing melting points
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What is Al2O3? but what does it show? why?
Ionic, some covalent character - can be explained by the electronegativity difference being less big or alternatively by the small aluminium ion with a high charge being able to get close to the oxide ion and distorting the oxide charge cloud
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How to prove above compounds contain ions experimentally
melt the solids and show they conduct electricity
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What are the macromolecular oxides
SiO2
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So what does it have
many very strong covalent bonds between atoms
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What does this require
high energy needed to break the many strong covalent bonds
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What does this result in
very high melting point and boiling point
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What are the simple molecular oxides
P4H10 (s), SO2 (g)- simple molecular
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What do they have
weak IM forces between molecules (VDW and permanent dipoles)
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so what do they have
lower melting points
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What are they and why
covalent because of the small electronegativity different between the non-metal and O atoms
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What is P4H10 (s) a molecule containing 4P's and 10O's compared to SO2(g)
Is a bigger molecule and has more electrons that so2 therefore have larger VDW forces and a higher MP
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What is aluminium metal protected from and what with
corrosion in moist air by a thin layer of aluminium oxide
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how
the high lattice strength of aluminium oxide and its insolubility in water make this layer impermeable to air and water
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Structure of SO2
S with 2 =O's on either side of the S and 2 electrons
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Structure of so3
S with 3=O's
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What do metal ionic oxides tend to react with
water to form hydroxides which are alkaline
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Na2O (s) + H2O (l)=
2Na+ (aq) + 2OH- (aq)
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What PH and type of rxn
13 and vigorous exothermic reaction
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What are the ionic oxides
basic
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why
oxide ions accept protons to become hydroxide ions in this reaction acting as a bronsted Lowry base
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MgO (s) + H2O (l) =
Mg(OH)2 (s)
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What ph
9
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What is Mg(OH)2
only slightly soluble in water as its lattice is stronger so fewer free OH- ions are produced and so lower ph
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What don't Al2O3 and SiO2 do and why
dissolve in water because of the high strength of the Al2O3 ionic lattice and SiO2 macromolecular structure
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so what do they give
a neutral ph 7
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Why is MgO better than NaOH for treating acid in rivers and the stomach
As it is only sparingly soluble and weakly alkaline so using an excess would not make the water excessively alkaline
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What do the non-metal, simple molecular, covalent, oxides react with
water to give acids
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P4O10 (s) + 6H2O (l) =
4H3PO4(aq) PH 0- vigorous exothermic reaction
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SO2(g) + H2O (l) =
H2SO3 (aq) (HSO3- + H+) ph 3 weak acid
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SO3 (g) + H2O (l)=
H2SO4 (aq) (H+ + HSO4-) PH 0
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Trend
Ionic metal oxides show basic behaviour and non-metal covalent oxides show acidic behaviour
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What does the slightly intermediate nature of the bonding in aluminium oxides reflected in
its amphoteric behaviour - its can act as both a base and an acid
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displayed H2SO4
S centre with 2=O's on one side then on other side two O-H
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Displayed h2so3
S with a =O and 2 O-H's
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H3PO4 displayed
P with =O and 3 O-H's
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What do basic oxides react with acids to make
salts
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Na2O (s) + 2HCl (aq) =
2NaCl (aq) + H2O (l)
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Na2O (s) + H2SO4(aq) =
Na2SO4(aq) + H2O (l)
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MgO (s) +2HCl (aq) =
MgCl2 (aq) + H2O (l)
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ionically - Na2O(s) + 2H+(aq) =
2Na + (aq) + H2O (l)
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ionically MgO (s) + 2H+(aq) =
Mg2+ (aq) + H2O (l)
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Rather than learning equations what should you know
Acid + base= salt + water (PO4^3-, SO4^2-)
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What can aluminium oxides act as
both an acid and an alkali and is therefore called amphoteric
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If acting as acid Al2O3(s) + 3H2SO4(aq) =
Al2(SO4)3 (aq) + 3H2O (l)
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Al2O3 + 6HCl =
2AlCl3 + 3H2O
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Ionically Al2O3 + 6H+
2Al3+ +3H2O
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Acting as acid Al2O3 (s) + 2NaOH (aq) +3H2O=
2NaAl(OH)4 (aq)
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ionically Al2O3 (s) +2OH- +3H2O
2Al(OH)4-(aq)
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What do the other simple molecular acidic oxides react with bases to form
salts
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P4O10 + 12NaOH (Aq)=
4Na3PO4(aq) +6H2O
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ionically P4O10 + 12OH-=
4PO4^3- +6H2O
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P4O10 +6Na2O =
4Na3PO4
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SO2 (g) + 2NaOH =
Na2SO3 +h2o
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ionically SO2 +2OH-=
so3^2- + h2o
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SO3 (g) +2NaOH
Na2SO4 +H2O
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ionically SO3 + 2OH- =
SO4^2- +H2O
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What is SiO2
giant covalent structure with v strong bonds that stops it dissolving or reacting with water and weak solutions of alkali
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What will it however react with
very conc NaOH
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eqn
2NaOH(l) +SiO2 (s) =Na2SiO3 (Aq) +H2O
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What is it still classed as :)
an acidic oxide
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Card 2

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how

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fizzes around on surface

Card 3

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EQN

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Card 4

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How does Magnesium react with cold water, to form

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Card 5

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What does it react more readily with, to form

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