Reactivity series
K – Potassium
Na – Sodium
Ca – Calcium
Mg – Magnesium
Al – Aluminium
C – Carbon
Zn – Zinc
Fe – Iron
Pb – Lead
H – Hydrogen
Cu – Copper
Ag – Silver
Au – Gold
Everything above Hydrogen can displace hydrogen from its acid, and hydrogen cannot reduce their oxides. Metals above carbon, their oxides cannot be reduced by carbon. An element can displace an other element from it’s oxide if it is more reactive e.g. copper oxide + zinc → copper + zinc oxide. More reactive metals will react with cold water, and
less reactive will react slowly or not react with steam.
(Paper 6: copper (II) oxide is a black solid)
The elements further up the reactivity series form more stable compounds and have a greater desire to exist in a compound than as an element, so:
-metals will displace a less reactive metal from its oxide or…
–displace a less reactive metal from a salt in a solution. Thermal decomposition:
Metal hydroxide → (heat) → metal oxide + water
This does not apply to potassium and sodium. It happens faster, the further you go down the reactivity series. All nitrates decompose on heating, but don’t all form the same products.
Potassium or sodium nitrate → (heat) → potassium or sodium nitrite + oxygen Metal nitrate (except K and Na) → (heat) → metal oxide + nitrogen dioxide + oxygen
Aluminium seems unreactive because it naturally forms an oxide layer which protects it.