Materials: Metals and Non-Metals

Reaction of metals with oxygen

Metal reacts with oxygen to form metal oxides.

                        Metal + oxygen → metal oxide

Different metals react differently depending upon their reactivity

1. Sodium and potassium react with oxygen present in air instantly so these are always placed in kerosene oil.

4Na + O₂ → 2Na₂O

2. Magnesium, zinc, aluminium, lead like metals combine slowly with oxygen present in air. These metals forms layer of metal oxide on their surface which is hard  and tough in nature. Due to this further reaction of these metals with oxygen is not possible. So these metals get protected by  these metal oxide layer.

4Al + 3O₂ → 2Al₂O₃

2Mg + O₂ → 2MgO

3. Iron don’t react with oxygen even on heating but iron powder react fastly with oxygen on adding in fire.

4. Silver and gold don’t React with oxygen.