Have you ever noticed how a hard iron object breaks easily with a light shove when it develops a red coating called rust? Or wondered where does the acid in acid rain come from? To answer all these questions, let us explore the Metallic and Non-Metallic Properties that play an important role in determining the behaviour of elements. As you have already studied, all elements can be classified into metals and non-metals, depending upon the behaviour they exhibit. In this section, let us discuss the Physical and Chemical properties of metals and non-metals.
Physical Properties of Metals
1. Reactions of Metals with Oxygen/ Burning in air
Have you noticed that iron doors and utensils develop a red coating after some time when exposed to air and moisture? Or that magnesium ribbon burns with a white flame?
To answer why this happens, let us look at the reaction of metals with oxygen in the air.
Most metals combine with oxygen to form metal oxides.
M + O2 → MmOn (basic),
where M is metal and MmOn is metal oxide
When copper, a reddish brown metal, reacts with oxygen, it forms copper oxide, which is black in colour.
All metals don’t react with oxygen at the same rate. They show different behaviours as follows:
2. Reactions of Metals with Water
Metals react with water to produce metal oxides and hydrogen gas.
M + H2O → MmOn + H2
where, M is metal and MmOn is metal oxide
Metal oxides that are soluble in water, dissolve to form metal hydroxides.
MmOn + H2O → MOH
where, MmOn is metal oxide and MOH is metal hydroxide
All metals react differently to water:
3. Reaction of Metals with Acids
Metals react with acids to give salt and hydrogen gas.
M + Acid → Salt + Hydrogen gas
where, M is metal
However, not all metals react in the same way.
4. Reaction of Metals with Solutions of other Metal Salts
When a more reactive metal displaces a less reactive metal from its salt solution, the reaction is called a Displacement reaction.
Metal M + Salt solution of N → Salt solution of M + Metal N
Here, in the first equation, iron (Fe) is more reactive than copper (Cu) so it displaces copper from copper sulphate (CuSO4) to form iron sulphate (FeSO4). In the second equation, copper (Cu) is more reactive than silver (Ag) and thus is able to displace it from silver nitrate (AgNO3) to form copper nitrate (Cu(NO3)).
The reactivity series is an arrangement of metals in the order of their decreasing activities.
|Potassium (K)||Increasing reactivity|
Physical Properties of Non-Metals
Chemical Properties Of Non-Metals
1. Reaction of non-metals with oxygen
Non-metals react with oxygen to form acidic or neutral oxides.
S(s) + O2(g) → SO2(g)
Here, sulphur (S) reacts with oxygen to form sulphur dioxide (SO2)
Some non-metal oxides react with water to form acids. This is one of the reasons for acid rains.
SO2(g) + H2O(l) → H2SO3(aq)
Here, sulphur dioxide (SO2) reacts with water to form sulphurous acid (H2SO3)
2. Reaction of non-metals with water
Non-metals do not react with water or steam to form hydrogen gas.
3. Reaction of non-metal with acids
Non-metals do not react with acids as when a substance reacts with acids it has to give electrons to the positive hydrogen ions produced by acids. However, non-metals are electron acceptors and not donators.
4. Reaction of non-metal with Salt Solution
Non-metals do not react with salt solutions but displace the less reactive non-metal from the salt.
|Physical State at room temperature||Solid (except Gallium and Mercury)||Gas or Solid (except Bromine)|
|Appearance||Lustrous or shiny||Non-lustrous or dull|
|Density||High density||Low density|
|Hardness||Hard (except sodium, potassium)||Soft (except diamond)|
|Melting and Boiling point||High Melting and Boiling point||Low Melting and Boiling point|
|Conduction||Good conductor of heat and electricity||Poor conductor of heat and electricity|
|Oxygen||React to form basic oxides||React to form acidic oxides|
|Acids||React to form hydrogen gas||Do not usually react|
Everything around us is made of metals or non-metals. The elements that show properties of both metals and non-metals are called metalloids. Eg. silicon, germanium, etc. We hope that you now have a better understanding of metallic and non-metallic properties.
To learn more about metals and non-metals, check out MSVgo,our interactive and engaging video library, which explains concepts with examples and explanatory visualisations and animations.