Students should refer to the below Metals and Non-Metals Class 10 notes prepared as per the latest curriculum issued by CBSE and NCERT. These notes and questions are really useful as they have been developed based on the most scoring topics and expected questions in upcoming examinations for Class 10. Metals and Non-Metals is an important topic in Science Class 10 which if understood properly can help students to get very good marks in class tests and exams.
Metals and Non-Metals Class 10 Notes and Questions PDF Download
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Elements can be classified as metals and non-metals on the basis of their properties
Physical properties of Metals
Metals are malleable, ductile, sonorous and good conductors of heat and electricity. They possess high melting and boiling point and have metallic lustre.
Examples- Cu, Mg, Al, Ag, Au etc.
Exceptions among metals-
(A) All metals are solid but mercury is a liquid at room temperature.
(B) Metals have high melting and boiling point, but Gallium and Caesium have very low melting point. These two metals will melt if you keep them on your palm.
(C) Alkali metals (Li,Na,K) are soft and can be easily cut with a knife. They have low densities and low melting point.
Physical properties of non metals
Non metals are non-malleable, non-ductile and bad conductors of heat and electricity. They possess low melting and boiling point.
Examples- C, S, P, N, O etc
Exceptions among non metals-
(A) Non metals are generally solids and gases except bromine which is liquid
(B) Iodine is a lustrous non metal
(C) Diamond is the hardest natural known substance
(D) Graphite is a good conductor of electricity
Chemical Properties of Metals
1. Reaction With Oxygen:
Metals react with air or oxygen to form metal oxide.
Metal + Oxygen —————→ Metal oxide
• 4Na + O2 ———–→ 2Na2O
• 2Mg + O2 ————-> 2 MgO
• 2Ca + O2 ————-> 2 CaO
Metal oxides are generally basic in nature as these oxides dissolve in water to form bases.
• Na2O + H2O—————–→ 2NaOH
• MgO + H2O ————–→ Mg(OH)2
• Copper when heated in air reacts with oxygen to form copper oxide.
2Cu + O2 → 2CuO
Similarly aluminium forms aluminium oxide.
• 4Al + 3O2 → 2Al2O3
Metal oxides which reacts with both acids as well as bases to form salts and water are known
as amphoteric oxides .e.g aluminium oxide, zinc oxide
Al2O3 + 6HCl ————–→ 2 AlCl3 + 3 H2O
Al2O3 + 2 NaOH ————–→ 2 NaAlO2 + H2O
ZnO +2NaOH————→ Na2ZnO2
2. Reaction with Water
Metals react with water to form metal hydroxide and hydrogen gas with a lot of heat. For
Example: 2Na + 2H2O → 2NaOH + H2
Most reactive metals like Na, K reacts vigorously with water at room temperature and catches fire due to the evolution of hydrogen gas.
So these metals should be stored in kerosene or paraffin wax to avoid reaction with water vapour at room temperature.
Metals like magnesium reacts with only boiling water
Mg + 2H2O → Mg(OH)2 + 2H2
However metals like Al, Fe, Zn react with steam
2Al + 3H2O → Al2O3 + 3H2
3Fe + 4H2O → Fe3O4 + 4H2
[But Aluminium is rendered passive with water or acid because Al reacts with air to form aluminium oxide. This oxide layer act as protective layer and prevents further reaction reaction]
3. Reaction with Acids:
Metals also reacts with dilute acids to form salt and hydrogen. For example, magnesium reacts with dilute hydrochloric acid to form magnesium chloride and hydrogen.
Metal + Acid → Metal Salt + Hydrogen
Mg + 2HCl → MgCl2 + H2
Zinc reacts with dilute acid to form ZnSO4 and hydrogen gas
Zn + H2SO4 ——–→ ZnSO4 + H2
Hydrogen gas is not produced when a metal reacts with nitric acid. It is because nitric acid is a strong oxidising agent, it oxidises the H2 produced to water and itself gets reduced to any of the nitrogen oxide (N2O, NO, NO2)
But Mg and Mn react with very dilute nitric acid
The series in which metals are arranged in the decreasing order of reactivity, it is known as Reactivity Series.
4. Displacement Reaction:
More reactive metal displaces less reactive metal from its salt solution. While a less reactive metal cannot displace a more reactive metal from it`s salt solution
Metal A +Salt of metal B—–→ Salt of metal A +Metal B
Fe + CuSO4 → FeSO4 + Cu
Zn + FeSO4 → ZnSO4 + Fe
Mg + ZnSO4 → MgSO4 + Zn
Ag+CuSO4 → No reaction
Reaction between Metals and Non-Metals
Generally, Metal and non-metal can react together to form ionic compounds.
e.g 2Na + Cl2 ————–→ 2NaCl
2Ca + O2 ————→ 2 CaO
Ions-Positively or negatively charged atoms are called ions. Ions are formed because of loss or gain of electrons.
Compounds formed by ionic bond i.e due to the complete transfer of electrons from a metal to a non-metal are known as ionic Compounds. Ionic bond is electrostatic attractive force between oppositely charged ions.
Formation of NaCl, MgCl2 & MgO
Properties of Ionic Compounds
• They are generally hard and crystalline solid.
• They have a high melting and boiling point because of strong attractive force between ions.
• They are soluble in water but insoluble in organic solvents such as ether etc.
• They are good conductors of electricity in molten and aqueous solution state but not in solid state.
Because in solid state ions cannot move freely.
Metallurgy: The extraction of metals from their ore and then refining them for use is called metallurgy
Steps involved in the extraction of metals from ore
A. Enrichment of Ores
The process of removing impurities from the ore. The processes used for removing the impurities from ore is based on the differences between the physical and chemical properties of impurities and the ore.
B. Conversion of ore into metal oxide
(a) Roasting: The sulphide ore is converted into oxides by heating in the presence of air.
2 ZnS + 3O2 + heat → 2ZnO + 2SO2
(b) Calcination: The carbonate ores are converted into oxides by heating in absence or limited supply of air.
ZnCO3+ Heat → ZnO + CO2
C. Reduction of Metal Oxide to Metal
(i) Metals that are lower in the reactivity series can be reduced by heating alone.
e.g (a) 2HgS + 3 O2 +Heat → 2 HgO + 2 SO2
(b) 2 HgO +Heat → 2 Hg + O2
(ii) Metals that are in the middle of reactivity series are reduced by heating with carbon.
e.g ZnO + C → Zn + CO
Highly reactive metals also reduce metal oxide with low reactivity.
3 MnO2 +4 Al → 3 Mn + 2 Al2O3 + Heat
(iii) Metals that are high up in the reactivity series are reduced by electrolytic reduction. e.g Na,
Mg and Ca are obtained by electrolysis of their molten chlorides. The metals are deposited at cathode, whereas, chlorine is liberated at the anode.
At Cathode: Na+ + e– → Na
At Anode: 2Cl– → Cl2 + 2e–
In electrolytic refining :
Impure metal is taken as taken as anode, thin pure metal strip is taken as cathode and water soluble salt of the metal to be refined is taken as electrolyte.
At Anode: M → Mn+ n + ne-
Impure metal Metal ions in solution
At Cathode: M+n +ne- → M
Metal ions Pure metal in solution
CORROSION OF METALS
CORROSION- The slow attack of atmospheric gases, moisture and acids on the surface of metals which results in the formation of a new layer of sulphide, carbonate, oxide etc to be formed on the surface. Corrosion of metals can be prevented by : Applying oil or grease.
By galvanization. (Coating with zinc)
By tinning. (Coating with tin)
By electroplating. (Coating a less reactive metal like chromium)
By alloying. (Making alloys
ALLOYS: Alloys are homogenous mixture of two or more than two metals or metals and non-metals
An alloy is a substance made by melting two or more elements together, at least one of them metal.
The components of alloys cannot be separated using physical means. An alloy is homogeneous and retains the properties of a metal, even though it may include metalloids or non-metals in its composition. Example – steel ( iron with non-metallic carbon or silicon respectively).