anyone give me the notes on s- block element class 11
Answers
Answer:I GOT IT IN 11
Na2SO4 . 10H2O is called Glauber’s salt
Anomalous Behaviour of Lithium
Lithium shows anomalous behaviour due to the following reasons:
1. It has the smallest size in its group.
2. It has very high ionization enthalpy and highest electronegativity in the group.
3. Absence of d-orbitals inits valence shell.
As a result, it differs from the other alkali metals in the following properties :
Lithium is harder than other alkali metals, due to strong metallic bond.
Lithium combines with O2 to form lithium monoxide, Li2O whereas other alkali metals form peroxides (M2O2) and superoxides (MO2).
Lithium, unlike the other alkali metals, reacts with nitrogen to form the nitride.
CBSE Class 11 Chemistry Notes The s-Block Elements
Li2CO3 ,LiF and lithium phosphate are insoluble in water while the corresponding salts of other alkali metals are soluble in water.
Li2CO3 decomposes on heating to evolve CO2 whereas other alkali metal carbonates do not.
Lithium nitrate on heating evolves O2 and NO2 and forms Li2O while other alkali metal nitrates on heating form their respective nitrites.
Diagonal Relationship
Lithium shows diagonal resemblance with magnesium [the element of group 2] and this resemblance is due to similar polarising power, i.e.,
[ionic charge / (ionic radius)2] of both these elements.
Lithium resembles magnesium in the following respects :
The atomic radius of lithium is 1.31 Å while that of magnesium is 1.34 Å.
The ionic radius of Li+i on is 0.60 Å, which is very close to that of Mg2+ ion (0.65 Å).
Lithium (1.0) and magnesium (1.2) have almost similar electronegativities.
Both Li and Mg are hard metals.
LiF is partially soluble in water like MgF2.
Both combine with O2 to form monoxides, e.g., Li2O and MgO.
Both LiOH and Mg(OH)2 are weak bases.
Both LiCI and MgCl2 are predominantly covalent.
Both Li and Mg combine with N2 to form their respective nitrides, Li3N and Mg3N2.
Both lithium and magnesium nitrates on heating evolve NO2 and O2 leaving behind their oxides.
Compounds of Sodium
1. Sodium Chloride, Common Salt or Table Salt [NaCI]
Sea water contains 2.7 to 2.9%by mass of the salt. Sodium chloride is obtained by evaporation of sea water but due to the presence of impurities like CaCl2 and MgCl2 it has deliquescens nature. It is purified by passing HCI gas through the impure saturated solution of
NaCl and due to common ion effect, pure NaCl gets precipitated. 28% NaCl solution is called brine.
2. Sodium Hydroxide or Caustic Soda [NaOH]
Methods of preparation
(i) A 10% solution of Na2CO3 is treated with milk of lime (Causticizing process).
CBSE Class 11 Chemistry Notes The s-Block Elements
(ii) Electrolytic process involves Nelson cell and Castner-Kellner cell.
A brine solution is electrolysed using a mercury cathode and a carbon anode. Sodium metal discharged at the cathode combines with Hg to form Na-amalgam. Chlorine gas is evolved at the anode.
The amalgam is treated with water to give sodium hydroxide and hydrogen gas.
2Na-Hg + 2H2O → 2NaOH + 2Hg + H2
Physical properties
Sodium hydroxide is a white translucent solid. It is readily soluble in water. Crystals of NaOH are deliquescent.
Chemical properties
1. It is a hygroscopic, deliquescent white solid, absorbs CO2 and moisture from the atmosphere
CBSE Class 11 Chemistry Notes The s-Block Elements
CBSE Class 11 Chemistry Notes The s-Block Elements
3. Sodium Carbonate or Washing Soda (Na2CO3 . 10H2O)
Solvay process
CO2 gas is passed through a brine solution saturated with NH3
CBSE Class 11 Chemistry Notes The s-Block Elements
Sodium bicarbonate is filtered and dried. It is ignited to give sodium carbonate.
CBSE Class 11 Chemistry Notes The s-Block Elements
Properties
1. Sodium carbonate crystallises from water as decahydrate which effloresces on exposure to dry air forming monohydrate which on heating change to anhydrous salt (soda-ash).
CBSE Class 11 Chemistry Notes The s-Block Elements
Uses
1. It is used in water softening, laundering and cleaning.
2. It is used in paper, paints and textile industries
4. Sodium Bicarbonate or Baking Soda (NaHCO3) Preparation
It is obtained as an intermediate product in Solvay process.
Properties
CBSE Class 11 Chemistry Notes The s-Block Elements
Uses
1. It is used as a constituent of baking powder which is a mixture of sodium bicarbonate, starch and potassium bitartrate or cream of tartar and in medicine to remove acidity of the stomach (as antacid).
2. NaHCO3 is a mild antiseptic for skin infections.
3 It is used in fire extinguisher.
Answer:
Na2SO4 . 10H2O is called Glauber’s salt
Anomalous Behaviour of Lithium
Lithium shows anomalous behaviour due to the following reasons:
1. It has the smallest size in its group.
2. It has very high ionization enthalpy and highest electronegativity in the group.
3. Absence of d-orbitals inits valence shell.
As a result, it differs from the other alkali metals in the following properties :
Lithium is harder than other alkali metals, due to strong metallic bond.
Lithium combines with O2 to form lithium monoxide, Li2O whereas other alkali metals form peroxides (M2O2) and superoxides (MO2).
Lithium, unlike the other alkali metals, reacts with nitrogen to form the nitride.
CBSE Class 11 Chemistry Notes The s-Block Elements
Li2CO3 ,LiF and lithium phosphate are insoluble in water while the corresponding salts of other alkali metals are soluble in water.
Li2CO3 decomposes on heating to evolve CO2 whereas other alkali metal carbonates do not.
Lithium nitrate on heating evolves O2 and NO2 and forms Li2O while other alkali metal nitrates on heating form their respective nitrites.
Diagonal Relationship
Lithium shows diagonal resemblance with magnesium [the element of group 2] and this resemblance is due to similar polarising power, i.e.,
[ionic charge / (ionic radius)2] of both these elements.
Lithium resembles magnesium in the following respects :
The atomic radius of lithium is 1.31 Å while that of magnesium is 1.34 Å.
The ionic radius of Li+i on is 0.60 Å, which is very close to that of Mg2+ ion (0.65 Å).
Lithium (1.0) and magnesium (1.2) have almost similar electronegativities.
Both Li and Mg are hard metals.
LiF is partially soluble in water like MgF2.
Both combine with O2 to form monoxides, e.g., Li2O and MgO.
Both LiOH and Mg(OH)2 are weak bases.
Both LiCI and MgCl2 are predominantly covalent.
Both Li and Mg combine with N2 to form their respective nitrides, Li3N and Mg3N2.
Both lithium and magnesium nitrates on heating evolve NO2 and O2 leaving behind their oxides.
Compounds of Sodium
1. Sodium Chloride, Common Salt or Table Salt [NaCI]
Sea water contains 2.7 to 2.9%by mass of the salt. Sodium chloride is obtained by evaporation of sea water but due to the presence of impurities like CaCl2 and MgCl2 it has deliquescens nature. It is purified by passing HCI gas through the impure saturated solution of
NaCl and due to common ion effect, pure NaCl gets precipitated. 28% NaCl solution is called brine.
2. Sodium Hydroxide or Caustic Soda [NaOH]
Methods of preparation
(i) A 10% solution of Na2CO3 is treated with milk of lime (Causticizing process).
CBSE Class 11 Chemistry Notes The s-Block Elements
(ii) Electrolytic process involves Nelson cell and Castner-Kellner cell.
A brine solution is electrolysed using a mercury cathode and a carbon anode. Sodium metal discharged at the cathode combines with Hg to form Na-amalgam. Chlorine gas is evolved at the anode.
The amalgam is treated with water to give sodium hydroxide and hydrogen gas.
2Na-Hg + 2H2O → 2NaOH + 2Hg + H2
Physical properties
Sodium hydroxide is a white translucent solid. It is readily soluble in water. Crystals of NaOH are deliquescent.
Chemical properties
1. It is a hygroscopic, deliquescent white solid, absorbs CO2 and moisture from the atmosphere
CBSE Class 11 Chemistry Notes The s-Block Elements
CBSE Class 11 Chemistry Notes The s-Block Elements
3. Sodium Carbonate or Washing Soda (Na2CO3 . 10H2O)
Solvay process
CO2 gas is passed through a brine solution saturated with NH3
CBSE Class 11 Chemistry Notes The s-Block Elements
Sodium bicarbonate is filtered and dried. It is ignited to give sodium carbonate.
CBSE Class 11 Chemistry Notes The s-Block Elements
Properties
1. Sodium carbonate crystallises from water as decahydrate which effloresces on exposure to dry air forming monohydrate which on heating change to anhydrous salt (soda-ash).
CBSE Class 11 Chemistry Notes The s-Block Elements
Uses
1. It is used in water softening, laundering and cleaning.
2. It is used in paper, paints and textile industries
4. Sodium Bicarbonate or Baking Soda (NaHCO3) Preparation
It is obtained as an intermediate product in Solvay process.
Properties
CBSE Class 11 Chemistry Notes The s-Block Elements
Uses
1. It is used as a constituent of baking powder which is a mixture of sodium bicarbonate, starch and potassium bitartrate or cream of tartar and in medicine to remove acidity of the stomach (as antacid).
2. NaHCO3 is a mild antiseptic for skin infections.
3 It is used in fire extinguisher.