22 Periodicity Flashcards
Magnesium and cold water
Mg(s) + 2H2O (l) ➡️ Mg(OH)2 (aq) + H2
Reaction slow at room temp
Mg(s) + H2O ➡️ MgO (s) + H2
Both redox reactions
Sodium and cold water
2Na(s) + 2H2O(l). ➡️ 2NaOH (aq) + H2 (g)
Vigorous
Sodium floats on the surface and fizzes rapidly
sodium
magnesium
aluminum
metallic
shiny (when freshly exposed to air)
conduct electricity
react with dilute acids to give hydrogen and salts
silicon
semi-metal (metalloid)
conduct electricity to some extent
semiconductor
Phosphorus
sulfur
chlorine
non-metals
do not conduct electricity
low melting and boiling points
argon
chemically unreactive
exists as separate atoms
sodium and oxygen
burns brightly in air
with a yellow flame (because of sodium peroxide Na2O2)
2Na (s) + 1/2 O2 (g) ➡️ Na2O (s)
period 3 and oxygen
relativity reactive
reactions are exothermic
magnesium and oxygen
strip of magnesium ribbon burns in air with a bright white flame
white power produced is magnesium oxide
2Mg (s) + O2(g) ➡️ 2MgO
aluminium and oxygen
burns brightly
4Al (s) + 3O2(g) ➡️ 2Al2O3
aluminium
reactive metal but it is always coated with a strongly bonded structure layer of oxide, this protects it from further reaction
so it appears as an unreceptive metal
silicon and oxygen
Si (s) + O2 (g) ➡️ SiO2 (s)
red phosphorus and oxygen
has to be heated before it will react with oxygen
4P(s) + 5O2(g) ➡️ P4O10(s)
white phosphorus and oxygen
spontaneously ignites in air
4P(s) + 5O2(g) ➡️ P4O10(s)
limited supply of oxygen
4P(s) + 5O2(g) ➡️ P2O3(s)
sulfur and oxygen
when sulfur powder is heated and lowered into a gas jar of oxygen, it burns with a blue flame to form the colourless gas sulfur dioxide
S(s) + O2(g) ➡️ SO2(g)
sodium oxide
magnesium oxide
aluminum oxide
giant ionic lattices
high melting points
Aluminum oxide
ionic but has some covalent character
small ion with a large positive charge
silicon oxide
ginat covalent (macromolecular) structure high melting point because many strong covalent bonds must be broken to melt it
phosphorus and sulfur oxide
covalently bonded molecules
intermolecule forces are weak van Der Waals and dipole-dipole forces
relatively low melting points
structure of sodium oxide
giant ionic
structure of magnesium oxide
giant ionic
structure of aluminium oxide
giant ionic
structure of silicon oxide
giant covalent ( macromolecular)
structure of phosphorus oxide
molecular
structure of sulfur oxide
molecular
sodium oxide (basic)
Na2O (s) + H2O (l) ➡️ 2Na+(aq) + 2OH-
pH = 14
Magnesium oxide (basic)
magnesium hydroxide is sparing soluble
MgO(s) + H20(l) ➡️ Mg(OH)2(s)
Mg(OH)2(s) Mg2+ (aq) + 2OH- (aq)
pH = 9
insoluble oxides
aluminium oxide and silicon dioxide are both insoluble in water
(silicon dioxide are sand)
phosphorus pentoxide and water (acidic )
phosphorus pentoxide reacts quite violently with water to produce an acid solution of phosphoric acid
P4O10(s) + 6H2O(l) ➡️ 4H3PO4(aq)
H3PO4(aq) H+(aq) + H2PO4-(aq)
pH = 1-2
sulfur dioxide and water (acidic)
sulfur dioxide is fairly soluble in water and reacts to give an acidic solution of sulphuric acid.
SO2(g) + H20(l) ➡️ H2SO3
H2SO3 H+ (aq) + HSO3-(aq)
pH = 2-3
sulfur trioxide and water (acidic)
sulfur triode reacts violently with water to produce sulphuric acid
SO3(g) + H2O(l) ➡️ H2SO4(aq) ➡️ H+(aq) + HSO4-(aq)
pH = 0-1
sodium and magnesium oxide and acids
react with an acids to give a salt and water only
Na2O(s) + H2SO4(aq) ➡️ Na2SO4(aq) + H2O(l)
MgO(s) + 2HCl (aq) ➡️ MgCl2(aq) +H2O
Aluminium oxide and acid
Al2O3(s) + 6HCl(aq) ➡️ 2AlCl3(aq) + 3H2O(l)
Aluminium oxide and alkali
Al2O3(s) + 2NaOH(aq) +3H2O ➡️ 2NaAl(OH)4(aq)
NaOH hot and concentrated
silicon dioxide and base
reacts a weak acid with a strong base
SiO2(s) + 2NaOH(aq) ➡️ Na2SiO3(aq) + H2O(l)
iron production
iron is produced in blast furnaces
calcium oxide reacts with the impurity silicon dioxide to produce a liquid slag.
SiO2(s) + CaO(l) ➡️ CaSiO3(l)
phosphorous pentoxide
reaction of phosphorus pentoxide with an alkali to make phosphorus acid
H3PO4(aq) + NaOH(aq) ➡️ NaH2PO4(aq) + H2O(l)
NaH2PO4(aq) + NaOH(aq) ➡️ Na2HPO4(aq) + H2O(l)
NaHPO4(aq) + NaOH(aq) ➡️ Na3PO4(aq) + H2O(l)
3NaOH(aq) + H3PO4(aq) ➡️ Na3PO4(aq) + 3H2O(l)
sulfur dioxyde and alkali
SO2(aq) + NaOH(aq) ➡️ NaHSO3(aq)
NaHSO3(aq) + NaOH(aq) ➡️ Na2SO3(aq) + H2O(l)
calcium sulfite
sulfur dioxide react with base calcium oxide to form calcium sulfite. this is the first step of one of the methods of removing sulfur dioxide from flue gases in power stations
CaO(s) + SO2(g) ➡️ CaSO3(s)
calcium sulfite is further converted to calcium sulphate and sold as gypsum for plastering
