Physical properties of metals:
(i) Metals are good conductors of heat and electricity.
(ii) Metals are malleable and ductile.
(iii) They are lustrous and can be polished.
(iv) Generally they are solid at room temperature except mercury.
(v) Metals generally have high melting and boiling points.

When a more reactive element displaces a less reactive element or molecule from its salt, such reactions are called displacement reactions. These reactions can be well explained in metals. When in copper sulphate solution zinc granules are added, the blue colour of copper sulphate disappears and a powdery red mass of copper is deposited at the bottom of the beaker. The reaction can be represented as follows:
\(\underset{(Blue)}{CuSO_4}+Zn⟶\underset{(Colourless)}{ZnSO_4}+\underset{(Red)}{Cu}\)

Iron is present in our blood. Red Blood Cells (RBCs) of blood contain a respiratory pigment known as haemoglobin. Each molecule of haemoglobin contains iron atom as its important component.

(a) When charcoal is burnt, carbon dioxide gas is produced. This gas turns lime water into milky colour. The nature of the gas can be tested by using aqueous solution of carbon dioxide on moist red and blue litmus paper. No effect on red litmus but the solution turns blue litmus to red, so it is acidic in nature .
(b) Equations of all the reactions are given as below:
Carbon + Oxygen\(\rightarrow \) Carbon dioxide 
Carbon dioxide + Lime water \(\rightarrow \) Milky
Carbon dioxide + Water \(\rightarrow \)Carbonic acid
Carbonic acid + Blue litmus\(\rightarrow \) Red litmus

No, we cannot store lemon pickle in aluminium utensil because aluminium is a metal and lemon contains acid. The acid reacts with metal to give hydrogen and salt. This salt is toxic in nature which will spoil the food and makes it unfit to use
Citric acid + Aluminium \(\rightarrow \) Aluminium salt + Hydrogen \(\uparrow \)
(From lemon)                      (Toxic)

Metals are used in making machinery, automobiles, aeroplane, trains, satellites, industrial gadgets, cooking utensils, water boilers etc.

Phosphorus.

Sodium metal.

Metals which can easily cut with a knife.These are soft metals. 
(i) Sodium
(ii) Potassium.

a) Chemical properties of metals:
(i) Metals react with oxygen to produce oxides which are alkaline in nature. e.g.,
\(\underset{Magnesium}{Mg}+\underset{Oxygen}{O_2}⟶\underset{Magnesium\ oxide}{2MgO}\)
(ii) Metallic oxides produce bases by reacting with water differently
\(\underset{Sodium\ oxide}{Na_2O}+\underset{Water}{H_2O}⟶\underset{Sodium\ hydroxide}{2NaOH}\)
(iii) Metals react with acid to produce hydrogen gas
\(\underset{Hydrochloric\ acid}{2HCI}+\underset{Sodium}{2Na}⟶\underset{Sodium\ chloride}{2NaCl}+\underset{Hydrogen}{H_2}\)
(iv) More reactive metals displace the less reactive metals from their compounds in an aqueous solution 
\(\underset{Copper\ Sulpahte}{CuSO_4}+\underset{Zinc}{Zn}⟶\underset{Zinc\ Sulphate}{ZnSO_4}+\underset{Copper}{Cu}\)
(b) Chemical properties of Non-metals
(i) Non-metals react with oxygen to produce oxides which are acidic in nature
\(\underset{Sulphur}{S}+\underset{Oxygen}{O_2}⟶\underset{Sulphur\ dioxide}{SO_2}\)
\(\underset{Sulphur\ dioxide}{SO_2}+\underset{Water}{H_2O}⟶\underset{Sulphurous\ Acid}{H_2SO_3}\)
(ii) Non-metals do not react with water.
(iii) Non-metals do not show displacement reactions.

Take about 50 mL of water in a beaker and dissolve 5 g of copper sulphate in it to obtain copper sulphate solution (which is blue in colour). Put a clean iron nail in this solution and keep the beaker undisturbed for sometime.
We will find that the blue colour of copper sulphate solution starts fading gradually and the iron nail gets covered with a red-brown layer of copper metal. It is because iron is more reactive than copper, so it displaces copper metal from its solution of copper sulphate. It is the copper metal set free from its compound which forms a red-brown layer on the surface of iron nail. This shows that iron is more reactive than copper.
Copper sulphate + Iron\(\rightarrow \) Iron sulphate + Copper
(Blue solution)      (Grey) (Greenish solution) (Red-brown)

Zinc can be beaten into thin sheets because zinc is a metal, while phosphorus, sulphur and oxygen are non-metals