Metals and Non-metals notes for class 10 is important for cbse board exam . It contains gist of lesson and important questions.
Elements are classified broadly into two categories on the basis of properties:
Metals: Iron, Zinc, Copper, Aluminium etc.
Non – metals: Chlorine, Nitrogen, Hydrogen, Oxygen, Sulphur etc.
Apart from metals and non-metals some elements show properties of both metals and non – metals,
e.g. Silicon, Arsenic, Germanium .They are called metalloids.
Metals and Non-metals notes for class 10
Comparison of physical and chemical properties of metals and non – metals:-
|1||Physical State||Metals are solid at room temperature. Except mercury and gallium.||Non-metals generally exist as solids and gases, except Bromine.|
|2||Melting and boiling points||Metals generally have high m.pt and b.pt except gallium and cesium.||Non-metals have low m.pt and b.pt except diamond and graphite.|
|3||Density||Generally high.||Generally low.|
|4||Malleability and Ductility||Malleable and ductile.||Neither malleable nor ductile.|
|5||Electrical and thermal conductivity||Good conductors of heat and electricity.||Generally poor conductors of heat and electricity except graphite.|
|6||Luster||Poses shining luster.||Do not have luster except iodine.|
Comparison of Chemical Properties of Metals and Non-metals:-
|1||Reaction with Oxygen||Metal + Oxygen → Metal oxide
4Na(s) + O2(g) → 2Na2O(s)
4Al(s) + 3O2(g) → 2Al2O3
Metals form basic oxides
Zn and Al form amphoteric oxides (they show the properties of both acidic and basic oxides) Most of the metal oxides are insoluble in water Some of them dissolve to form Alkali Na2O(s) + H2O(l) → 2NaOH(aq)
|Non-metal + Oxygen → Non-metaloxide
C + O2 → CO2
S + O2 → SO2
Non-metals form acidic oxides CO and H2O are neutral oxides(they are neither acidic nor basic in nature) Non-metal oxides are soluble in water They dissolve in water to form acids SO2 + H2O → H2SO3
|2||Reaction with water||Metals react with water to form metal oxides or metal hydroxide and H2 gas is released. 2Na(s) + 2H2O(l) → 2NaOH + H2(g) + heat||Non-metals do not react with water, steam to evolve hydrogen gas. Because Non-metals cannot give electrons to hydrogen in water so that it can be released as H2 gas.|
|3||Reaction with dilute Acids||Metal + Acid → Metal salt + Hydrogen
HCl Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
H2SO4 2Na(s) + H2SO4 → Na2SO4(aq) +H2(g)
HNO3 Metal + HNO3 → H2 gas is not displaced. Reason- HNO3 is strong oxidizing agent.
|Non-metals do not react with acids to release H2 gas
Reason- Non-metals cannot loose electrons and give it to Hydrogen ions of acids so that the gas is released.
Mn + 2HNO3 → Mn(NO3)2 + H2 H2 gas from HNO3
|4||Reaction with salt solutions||When metals react with salt solution, more reactive metal will displace a less reactive metal from its salt solution.
CuSO4(aq) + Zn(s) → ZnSO4(aq) + Cu(s)
|When non-metals react with salt solution, more reactive non-metal will displace a less reactive non-metal from its salt solution. 2NaBr(aq) + Cl2(g)→ 2NaCl(aq) + Br2(aq)|
|5||Reaction with Chlorine||Metal + Chlorine → Metal Chloride ionic bond is formed. Therefore Ionic compound is obtained. 2Na + Cl2 → 2NaCl||Non-metal + Chlorine → Non-metal Chloride covalent bond is formed. Therefore covalent compound is obtained.
H2(g) + Cl2 → 2HCl
|6||Reaction with Hydrogen||Metals react with hydrogen to form metal hydride This reaction takes place only for most reactive metals. 2Na(s) + H2(g) → 2NaH(s)||Non-metals react with hydrogen to form hydrides
H2(g) + S(l) → H2S(g)
Properties of ionic compounds
- Physical nature:solid and hard due to strong force of attraction. (generally brittle)
- Melting point and boiling point:have high M.P and B.P, as large amount of heat energy is required to break strong ionic attraction.
- Solubility: soluble in water and insoluble in kerosene and pertrol.
- Conduction of electricity: Ionic compounds in solid state does not conduct electricity.
Reason 1 – Ions can not move due to rigid solid structure. Ionic compounds conduct electricity in molten state.
Reason 2 – Ions can move freely since the electrostatic forces of attraction between the oppositely charged ions are overcome due to heat.
Occurrence of Metal
Metal occur in Earth Crust and Sea water.
Minerals –Elements or compounds, occuring naturally in the earth’s crust
Ores – Minerals that contain a particular metal in high percentage and can be extracted economically on a large scale.
Ex- Bauxite – Aluminium Ore
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