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