Period 3 elements and their oxides Flashcards
Describe and explain which is more reactive sodium or magnesium
Na
Because it requires less energy to remove one electron to form Na+ ion than to remove 2 electrons and form Mg2+ ion
Describe and write an equation for the reaction of sodium with water
2Na(s)+2H2O(l)> 2NaOH(aq) + H2(g)
Vigorously reacts with cold water
Forms a ball and fizzing
write an equation for the reaction of Mg with cold water/ then steam
Mg(s) + 2H2O(l) > Mg(OH)2(aq) + H2(g)
Mg(s) + H2O(g) > MgO + H2
Formula of Sodium Oxide
Na2O
Formula of Magnesium Oxide
MgO
Formula of Aluminium oxide
Al2O3
Formula of oxide of silicon
SiO2
Formula of phosphorus in its natural state
P4
Formula of phosphorous oxide
P4O10
Most readily made oxide of sulfur
SO2
Describe the reations of all the period 3 elements with air
Na - very fast
Mg - very fast
Al - slow (fast if powdered)
Si - slow
P - spontaneously combusts
S - steadily burns
Describe and explain the trend in boiling points of all the metal period 3 element oxides
Na2O, MgO and Al2O3 all have high boiling points due to their giant ionic lattice structure
MgO has a higher bp than Na2O because the electrostatic force of attraction is stronger because of Mg2+ ions instead of Na+ ions
Al2O3 has a lower bp than MgO because Al3+ ions distort electron cloud giving compound some covalent character
Describe and explain the trend in boiling points of all the non-metal period 3 element oxides
SiO2 has lower Bp than Al2O3 but is still relatively high (higher than all the non-metal oxides) due to macromolecular structure - requiring lots of energy to overcome the many covalent bonds
P4O10 and SO2/3 are both simple molecular structures so both have lower bps.
P4O10 has higher bp than SiO2 because of higher Mr which means VdWs are stronger
Which oxides form alkaline solutions in water
Na2O and MgO
Reaction of sodium oxide in water and describe effect on pH
Na2O + H2O > 2NaOH
Dissolves readily
pH 12-14
Reaction of magneisum oxide in water and describe effect on pH
MgO + H2O > Mg(OH)2
Sparingly soluble
Weaker alkaline pH 9-10W
Which forms a more alkaline solution in water MgO or Na2O
Na2O
Reaction of phosphorus oxide in water
P4O10 + 6H2O > 4H3PO4
Reaction of sulfur dioxide in water
SO2+ H2O > H2SO3
Sulfur dioxide/ trioxide and phosphorus (v) oxide are both simple molecular structures.
What is the effect on pH when both of them react with water and why
pH of 0-2
triprotic H3PO4 releases more H+ than diprotic H2SO3 / H2SO4 when they dissociate
so forms more acidic solution
Reaction of sulfur trioxide in water
SO3 + H2O > H2SO4
Explain if and how silicon dioxide reacts with water
SiO2 insoluble in water
Reacts with a base to form a salt so classed as an acid
Explain reaction of Al2O3 with water
Amphoteric due to covalent and ionic character
Reacts with both acids and bases to form salts
Write an equation for the reaction of magnesium oxide with hydrochloric accid
MgO + 2HCl > MgCl2 + H2O
Write an equation for the reaction between sodium oxide and sulfuric acid
H2SO4 + Na2O > Na2SO4 + H2O
Write an equation for the reaction between SiO2 with a base such as Potassium Hydroxide
SiO2 + 2KOH > K2SiO3 + H2O
Write an equation for the reaction between PHOSPHORUS OXIDE with a base such as Potassium Hydroxide
P4O10 + 12KOH > 4K3PO4 + 6H2O
Write an equation for the reaction between SULFUR DIOXIDE with a base such as Potassium Hydroxide
SO2 + KOH > K2SO3 +H2O
Write an equation for the reaction between SULFUR TRIOXIDE with a base such as Potassium Hydroxide
SO3 + KOH > K2SO4 + H2O
Name the basic oxides
Magnsium and Sodium oxide
Name the acidic oxides
SiO2
SO2
SO3
P4O10
Name the amphoteric oxide
Al2O3
Reaction of Al2O3 with acid H2SO4
3H2SO4 + Al2O3 > Al2(SO4)3 + 3H2O
Reaction with Al2O3 with base NaOH
Al2O3 + NaOH > 3H2O + 2NaAl(OH)4
What is formed when Al2O3 reacts with a base
Al(OH)4- which reacts with metal ion
SiO2 + 2OH forms what
SiO3 2- ions
