Period 3 Elements with Oxygen
Element Chemical Equation Reaction Conditions Reaction Flame Product
Observation
Na, Sodium 4Na (s) + O2 (g) à 2Na2O (s) Heated Vigorous Yellow flame White solid
2Na (s) + O2 (g) à Na2O2 (s) Heated Vigorous Yellow flame Yellow solid
Mg, Magnesium 2Mg (s) + O2 (g) à 2MgO (s) Heated Vigorous White flame White solid
Al, Aluminium 4Al (s) + 3O2 (g) à 2Al2O3 (s) Room temperature Vigorous None White solid
Si, Silicon Si (s) + O2 (g) à SiO2 (s) Heating Slow White flame White solid
P, Phosphorus P4 (s) + 3O2 (g) à 2P2O3 (s) Heating, low air supply Slower than P(V) White flame White solid
P4 (s) + 5O2 (g) à 2P2O5 (s) Heating, excess air supply Vigorous White flame White solid
S, Sulphur S (s) + O2 (g) à SO2 (g) The temperature is 450 °C Vigorous Pale blue flame Colourless gas
and a vanadium (V) oxide
SO2 (g) + O2 (g) ↔ 2SO3 (g) (V2O5) catalyst is used Vigorous Pale blue flamer Colourless
liquid
Chlorine oxides have to be made indirectly
Chlorine Oxide Colour State at 298K
Cl2O Yellow Gas
ClO2 Orange Gas
Cl2O2 Red Liquid
Cl2O7 Colourless Liquid
Period 3 Elements with Water
Element Chemical Equation Reaction Observations Reaction Product pH of
Solution
Na, Sodium 2Na (s) + 2H2O (l) à 2NaOH (aq) + H2 (g) Sodium floats, it melts into a ball and Vigorous Sodium is oxidised from 12-14
skates on the surface of the water, 0 to 1+ as seen in NaOH
orange flame sometimes seen
Mg, Mg (s) + 2H2O (l) à Mg(OH)2 (aq) + H2 (g) Only a few cm3 of hydrogen gas collected Very slow Magnesium oxided 10
Magnesium across several days, magnesium sinks from 0 to 2+
Mg (s) + H2O (g) à MgO (s) + H2 (g) Burns vigorously with a white flame Vigorous White magnesium
oxide solid
Element Chemical Equation Reaction Conditions Reaction Flame Product
Observation
Na, Sodium 4Na (s) + O2 (g) à 2Na2O (s) Heated Vigorous Yellow flame White solid
2Na (s) + O2 (g) à Na2O2 (s) Heated Vigorous Yellow flame Yellow solid
Mg, Magnesium 2Mg (s) + O2 (g) à 2MgO (s) Heated Vigorous White flame White solid
Al, Aluminium 4Al (s) + 3O2 (g) à 2Al2O3 (s) Room temperature Vigorous None White solid
Si, Silicon Si (s) + O2 (g) à SiO2 (s) Heating Slow White flame White solid
P, Phosphorus P4 (s) + 3O2 (g) à 2P2O3 (s) Heating, low air supply Slower than P(V) White flame White solid
P4 (s) + 5O2 (g) à 2P2O5 (s) Heating, excess air supply Vigorous White flame White solid
S, Sulphur S (s) + O2 (g) à SO2 (g) The temperature is 450 °C Vigorous Pale blue flame Colourless gas
and a vanadium (V) oxide
SO2 (g) + O2 (g) ↔ 2SO3 (g) (V2O5) catalyst is used Vigorous Pale blue flamer Colourless
liquid
Chlorine oxides have to be made indirectly
Chlorine Oxide Colour State at 298K
Cl2O Yellow Gas
ClO2 Orange Gas
Cl2O2 Red Liquid
Cl2O7 Colourless Liquid
Period 3 Elements with Water
Element Chemical Equation Reaction Observations Reaction Product pH of
Solution
Na, Sodium 2Na (s) + 2H2O (l) à 2NaOH (aq) + H2 (g) Sodium floats, it melts into a ball and Vigorous Sodium is oxidised from 12-14
skates on the surface of the water, 0 to 1+ as seen in NaOH
orange flame sometimes seen
Mg, Mg (s) + 2H2O (l) à Mg(OH)2 (aq) + H2 (g) Only a few cm3 of hydrogen gas collected Very slow Magnesium oxided 10
Magnesium across several days, magnesium sinks from 0 to 2+
Mg (s) + H2O (g) à MgO (s) + H2 (g) Burns vigorously with a white flame Vigorous White magnesium
oxide solid
