3.2.4 Properties of Period 3 elements and their oxides Flashcards
What are the period 3 elements you need to know about?
of course can look at PT but just because..
Na
Mg
Al
Si
P4
S8
what colour are the period 3 elements?
sodium: silvery white
magnesium: silvery white
aluminium: silvery white
silicone: dark grey
phosphorus: white
sulfur: pale yellow
what is the general trend in atomic radius going across period three?
why
descreases
(increasing nuclear charge same shielding–> stronger attraction with outer electrons)
what is the general trend in electronegativity going across period 3
why
increases
(increasing nuclear charge same shielding, decreasing atomic radius)–> stronger attraction
what is the general trend in ionisation energy going across period 3
why
increases
(increasing nuclear charge same shielding, decreasing atomic radius)–> stronger attraction
What structure does each period 3 ELEMENT have?
sodium: metallic
magnesium: metallic
aluminium: metallic
silicone: giant covalent
phosophorus: molecular
sulfur: molecular
Which elements of period 3 react with water
give equations
soium and magnesium only
2Na(s) + 2H2O(l) –> 2NaOH(aq) + H2(g)
Mg(s) + H2O(g) –> MgO(s) + H2(g)
(steam - fast)
Mg(s) + 2H2O(l) –> Mg(OH)2(s) + H2(g)
(water - slow)
equation for
Sodium and oxygen
4Na(s) + O2(g) –> 2Na2O(s)
equation for
magnesium and oxygen
2Mg(s) + O2(g) –> 2MgO(s)
equation for
aluminium and oxygen
4Al(s) + 3O2(g) –> 2Al2O3(s)
equation for
silicone and oxygen
Si(s) + O2(g) –> SiO2(s)
equation for
phosphorus and oxygen
P4(s) + 5O2(g) –> P4O10(s)
equations for
sulfur and oxygen
S(s) + O2(g) –> SO2(g)
2SO2 (g) + O2(g) ⇌ 2SO3 (g)
reacts further
flame colour of period 3 elements
or element cotaining compounds
sodium: yellow
magnesium: white
aluminium: white
silicone: N/A
phosphorus: white
sulfur: blue
structure of Na2O
ionic
structure of MgO
Ionic
structure of Al2O3
ionic
structure of SiO2
giant covalent
Structure of P4O10
need to visualise too
molecular
structure of SO2,SO3
need to visualise
molecuar
Which period 3 oxides will react with water (soluble)
Na2O
MgO
P4O10
SO2,SO3
equation for
Na2O and water
and what is the pH of resulting solution
Na2O + H2O –> 2NaOH
(O2- + H2O –> 2OH-)
~14 (more soluble)
equation for
MgO and water
and what is the pH of resulting solution
MgO + H2O –> Mg(OH)2
O2– + H2O –> 2OH–
~ 9 (only slightly soluble so less OH- are released)
equation for
P4O10 and water + what is the product called?
and what is the PH of resulting solution
P4O10 + 6H2O –>4H3PO4
(phosphoric acid)
~1
equation for
SO2 and water + what is the product called?
and what ius the pH of the resulting solution?
SO2 + H2O ⇌ H2SO3 (sulfurous acid)
~2-3
equation for
SO3 and water + what is the product called?
and what is the pH of the resulting solution?
SO3 + H2O ⇌ H2SO4 (sulfuric acid)
~1
what is the structure (visual) of phosphoric acid
tetrahedral
what is the (visual) structure of sulforous acid
trigonal pryamidal
what is the (visual) structure of sulfuric acid
tetrahedral
how (acid/base) does each period three oxide behave?
Na2O: basic (reacts with acid)
MgO: basic (reacts with acid)
Al2O3: amphoteric (reacts with acid)&(reacts with bases) (can act as both an acid and a base)
SiO2: acidic (reacts with base)
P4O10: acidic (reacts with base)
SO2,SO3: acidic (reacts with base)
acid/base reaction
NaO2
Na2O + 2H+ –> 2Na+ + H2O
acid/base reaction
MgO
MgO + 2H+ –> Mg2+ + H2O
acid/base reaction
Al2O3
(acts as base) Al2O3 + 6H+ –> 2Al3++ 3H2O
(acts as acid) Al2O3 + 2OH– + 3H2O –> 2Al(OH)4–
acid/base reaction
SiO2
SiO2 + 2OH– –> SiO3 2– + H2O
(must be hot, concentrated NaOH)
acid/base reaction
P4O10
P4O10 + 12OH– –> 4PO4 3– + 6H2O
acid/base reaction
SO2
SO2 + 2OH– –>SO3 2–+ H2O
acid/base reaction
SO3
SO3 + 2OH- –> SO4 2- + H2O
Describve the trend in melting point of period 3 oxides
Describe the trend in melting point of oxides
