Metal + Oxygen Reactions Tutorial
- All metals react with oxygen except silver (Ag(s)), platinum (Pt(s)) and gold (Au(s)).
- In general, metals react with oxygen to form metal oxides.
metal + oxygen → metal oxide
Group 1 metals, except lithium, produce compounds containing more oxygen:
Sodium produces sodium peroxide (Na2O2)
Potassium, rubidium and cesium produce metal superoxides (MO2)
- In general, metal oxides are ionic compounds#.
Metal atoms, M, lose electrons, ne-, to form positive ions (cations), Mn+:
M(s) → Mn+ + ne-
Oxygen gas, O2(g), is made up of 2 oxygen atoms, O.
Oxygen atoms, O, gain 2 electrons, 2e-, to form negative ions (oxide anions), O2-:
O + 2e- → O2-
Mn+ are attracted to O2- because they have opposite charges. This is called an ionic bond.
A compound containing only ionic bonds is called an ionic compound.
- The ease with which a metal reacts is known as its activity.
A more active metal will react more readily with oxygen than a less active metal.
- In general, Group 1 (IA or alkali) metals and Group 2 (IIA or alkaline earth) metals are more active than transition metals.
- Silver, gold and platinum are not active metals. They are known as noble metals## (or as inactive metals).