3.2.4 properties of period 3 elements and their oxides Flashcards
write a balanced equation for the reaction of sodium with water
2Na(s) + 2H2O — 2NaOH (aq) + H2 (g)
state 3 observations from the reaction between sodium and water
fizzing due to H2 produced
sodium floats on water and reacts vigorously forming molten ball
phenolphthalein goes from colourless to pink
write a balanced equation for the reaction of magnesium and water
Mg(s) + 2H2O (l) — Mg(OH)2 (s) + H2(g)
state an observation for the reaction between water and magnesium
reacts very slowly with cold water so no observable reaction
write a balanced equation for the reaction of magnesium and steam
Mg(s) + H2O(g) — MgO(s) + H2(g)
state an observation for the reaction between magnesium and steam
white powder
bright white flame
write a balanced equation for the reaction between sodium and oxygen
4Na(s) + O2(g) — 2Na2O(s)
what is the bonding and structure of the oxide produced between sodium and oxygen?
giant ionic lattice
ionic bonding
explain the melting point of sodium oxide
high melting point because it requires lots of energy to overcome the strong electrostatic forces of attraction between oppositely charged ions in a lattice
what is an observation from the reaction between sodium and oxygen?
very vigorous reaction, burns with a yellow flame forming sodium oxide which is a white solid
write a balanced equation for the reaction between magnesium and oxygen
2Mg(s) + O2(g) — 2MgO(s)
what is the structure and bonding of the oxide produced from the reaction between magnesium and oxygen?
giant ionic lattice and ionic bonding
explain the melting point of magnesium oxide
high melting point because there is lots of energy required to overcome the strong electrostatic forces of attraction between oppositely charged ions held together in a lattice
what can be observed in the reaction between magnesium and oxygen?
very vigorous reaction, burns with a bright white flame forming magnesium oxide which is a white solid
write a balanced equation for the reaction between aluminium and oxygen
4Al(s) + 3O2(g) — 2Al2O3 (s)
what is the structure and bonding of aluminium oxide?
giant ionic lattice
ionic bonding
explain the melting point of aluminium oxide
high melting point so lots of energy required to overcome electrostatic forces of attraction between oppositely charged ions held together in a lattice
state an observation from the reaction between aluminium and oxygen
vigorous reaction with a bright white flame forming aluminium oxide which is a white solid
write a balanced equation for the reaction between silicon and oxygen
Si(s) + O2(g). — SiO2 (s)
what is the structure and bonding in silicon dioxide
macromolecular
covalent bonding
explain the melting point of silicon dioxide
high melting point so lots of energy required to overcome many strong covalent bonds
state what is observed in the reaction between silicon and oxygen
a slow reaction
write a balanced equation for the reaction between phosphorus and oxygen
P4(s) + 5O2 (g) — P4O10 (s)
what is the bonding and structure of phosphorus (v) oxide
simple molecular
covalent bonding
explain the melting point of phosphorus (v) oxide
low melting point since there are weak van der waals between molecules that are easy to overcome
state an observation for the reaction between phosphorus and oxygen
vigorous reaction forming masses of white fumes with a white flame
write a balanced equation for the reaction between sulfur and oxygen
s(s) + O2(g) — sO2 (g)
what is the structure and bonding of sulphur dioxide?
simple molecular
covalent bonding
explain the melting point of sulphur dioxide
low melting point because there are weak van der waals between molecules that are easy to overcome
state what is observed in the reaction between sulphur and oxygen
melts easily then burns with a blue flame forming sulphur dioxide a colourless gas with a choking smell
at high temperature and with a catalyst, SO3 can form from the reaction between sulphur and oxygen, write an equation
S(s) + 1 1/2 O2(g) — SO3(g)
what is the PH of the solution formed after sodium and water react?
12-14
what is the PH of the solution formed after magnesium and water react?
9-10
write a balanced equation to show the reaction between Na2O with water
Na2O(s) + H2O (l) — 2NaOH(aq)
what is the PH of the solution formed from the reaction between Na2O and water
12-14
write a balanced equation to show the reaction between MgO and water
MgO(s) + H2O(l) — Mg(OH)2 (aq)
what is the PH of the solution formed from the reaction between MgO and water
9-10
write a balanced equation for the reaction between Al2O3 and water
aluminium is insoluble
what is the PH of the solution formed from the reaction between Al2O3 and water
no PH change as its insoluble
write a balanced equation for the reaction between P4O10 and water
p4o10(s) + 6H2O(l) — 4H3PO4(aq)
what is the PH of the solution formed from the reaction between p4o10 and water
0-1
write a balanced equation for the reaction between SO2 and water
silicon is insoluble in water
what is the PH of the solution formed from the reaction between SO2 and water
no PH change
what is the PH of the solution formed from the reaction between SO2 and water
no PH change
write a balanced equation for the reaction between SO3 and water
SO3 + H2O — H2SO4
what is the PH of the solution formed from the reaction between SO3 and water
0
write an equation for a reaction between Na2O and H2SO4 and a base
acid : Na2O (s) + H2SO4 (aq) — Na2SO4 (aq) + H2O(l)
base : not applicable
write an equation for the reaction between MgO and HCl and a base
acid : Mgo (s) + 2HCl (aq) — MgCl2 (aq) + H2O (l)
base : not applicable
write an equation for the reaction between Al2O3 and HCl and NaOH
acid : Al2O3 (s) + 6HCl — 2AlCl3 + 3H2O
base : Al2O3 (s) + 2NaOH (aq) + 3H2O — 2NaAl(OH)4 (aq)
write an equation for the reaction between p4o10 and NaOH and an acid
acid : no reaction
base : p4o10 (s) + 12NaOH (aq) — 4Na3PO4 (aq) + 6H2O (l)
write an equation for the reaction between SiO2 and NaOH and an acid
acid : no reaction
base : SiO2 (s) + 2NaOH (aq) — Na2SiO3 (aq) + H2O (l)
H3PO4 : write three equations, each showing the loss of an acidic hydrogen to form three anions
H3PO4 (aq) — H+ (aq) + H2PO4- (aq)
H3PO4 (aq) — 2H+ (aq) + HPO4 2- (aq)
H3PO4 (aq) — 3H+ (aq) + PO4 3- (aq)
H2SO3 : write two equations each showing the loss of an acidic hydrogen to form two different anions.
H2SO3 (aq) — H+ (aq) + HSO3- (aq)
H2SO3 (aq) — 2H+ (aq) + SO3 2- (aq)
H2SO4 : write two equations each showing the loss of an acidic hydrogen to form two different anions.
H2SO4 (aq) — H+ (aq) + HSO4 - (aq)
H2SO4 (aq) — 2H+ (aq) + SO4 2- (aq)
what is the shape of H3PO4?
tetrahedral
what is the shape of H2SO3?
trigonal pyramidal
what is the shape of H2SO4?
tetrahedral
predict whether the melting point of lithium oxide is higher than, the same as, or lower than the melting point of sodium oxide and explain your prediction
higher
because the Li+ ion is smaller than the Na+ ion so attracts O2- more strongly
in K, what is the avg. melting point of Na2O?
1548
in K, what is the avg. melting point of MgO?
3125
in K, what is the avg. melting point of Al2O3?
2345
in K, what is the avg. melting point of SiO2?
1883
in K, what is the avg. melting point of p4o10?
573
in K, what is the avg. melting point of SO2?
200
in K, what is the avg. melting point of SO3?
290
explain why sodium oxide forms an alkaline solution when it reacts in water
sodium oxide contains O2- ions which react with H2O to form OH- ions
write an ionic equation for the reaction of phosphorus oxide with an excess of sodium hydroxide solution
P4O10 + 12OH- — 4PO4 3- + 6H2O
why is phosphorus stored under water?
to prevent it from reacting with oxygen
how could you distinguish between the colourless gases of SO2 and SO3?
dissolve in separate samples of water and test PH, more acidic solution is SO3
predict whether the melting point of lithium oxide is higher than, the same as, or lower than the melting point of sodium oxide and explain your prediction
higher
Li+ ion is smaller than Na+ ion so attracts O2- more strongly
explain why magnesium has a higher melting point than sodium
Mg+ has a higher charge than Na+ so attracts delocalised electrons more strongly
other than a high melting point, give two physical properties of silicon dioxide that are characteristic of its structure and bonding
hard
insoluble
phosphorus (v) oxide is known as pentoxide suggest why it is usually represented by p4o10 rather than p2o5
one molecule contains 4 P and 10 O
explain why an excess of magnesium oxide can be used for neutralisation
MgO is sparingly soluble
explain why the use of excess sodium hydroxide to neutralise phosphoric acid solution might lead to environmental problems
excess of sodium hydroxide would make the lake toxic
suggest why sulfur dioxide forms a weakly acidic solution
reaction is an equilibrium
suggest why silicon dioxide is described as an acidic oxide even though it is insoluble in water
SiO2 reacts with bases
explain why the melting point of magnesium is higher than that of sodium
magnesium has a higher nuclear charge than sodium
it is a smaller atom meaning there is a strong attraction between the ions and delocalised electrons
explain how metals conduct electricity
through a sea of delocalised electrons that flow in a given direction
state and explain the trend in the melting points of the period 3 metals Na, Mg and Al
increases
nuclear charge increases
stronger attraction between cations and delocalised electrons
in terms of atomic structure, explain why the van der waals forces in liquid argon are very weak
argon particles are single atoms with electrons closer to the nucleus so cannot be easily polarised
explain why the second ionisation energy of sodium is greater than the second ionisation energy of magnesium
Na2+ requires loss of electron from 2p orbital
state why more than minimum energy is not used to ionise the sample of indium
so more than one electron is knocked out
explain why nickel is ductile
layers of ions can slide over one another
state one reason why the first ionisation energy of rubidium is lower than the first ionisation energy of sodium
rubidium is a bigger atom
state one reason why the first ionisation energy of rubidium is lower than the first ionisation energy of sodium
rubidium is a bigger atom