Which of the following does not illustrate the anomalous properties of Li?
Which of the following does not illustrate the anomalous properties of Li?
The correct option is C Li is much softer than the other I group metals
Anomalous behavior of lithium is due to extremely small size of lithium. Its cation on account of small size and high nuclear charge, lithium exerts the greatest polarizing effect out of all alkali metals on negative ion. Consequently, lithium ion possesses remarkable tendency towards solvation and develops covalent character in its compounds. Li differs from other alkali metals in the following respects:
(1) It is comparatively harder than other alkali metals. Li cannot be stored in kerosene as it floats to the surface, due to its very low density. Li is generally kept wrapped in paraffin wax.
(2) It can be melted in the dry air without losing its brilliance.
(3) Unlike other alkali metals, lithium is least reactive among all. It can be noticed by the following properties,
(i) It is not affected by air.
(ii) It decomposes water very slowly to liberate H2.
(iii) It hardly reacts with bromine while other alkali metals react violently.
(4) Lithium is the only alkali metal which directly reacts with N2 to form lithium nitride (Li3N)
(5) Lithium when heated in NH3 forms amide, Li2NH while other metals form amides, MNH2.
(6) When burnt in air, lithium form Li2O sodium form Na2O and Na2O2 other alkali metals form monoxide, peroxide and superoxide.
(7) Li2O is less basic and less soluble in water than other alkali metals.
(8) LiOH is a weaker base than NaOH or KOH and decomposes on heating.
(9) The ion of Li and its compounds are more heavily hydrated than those of the rest of the group
Hence, option B is correct.
Anomalous behavior of lithium is due to extremely small size of lithium. Its cation on account of small size and high nuclear charge, lithium exerts the greatest polarizing effect out of all alkali metals on negative ion. Consequently, lithium ion possesses remarkable tendency towards solvation and develops covalent character in its compounds. Li differs from other alkali metals in the following respects:
(1) It is comparatively harder than other alkali metals. Li cannot be stored in kerosene as it floats to the surface, due to its very low density. Li is generally kept wrapped in paraffin wax.
(2) It can be melted in the dry air without losing its brilliance.
(3) Unlike other alkali metals, lithium is least reactive among all. It can be noticed by the following properties,
(i) It is not affected by air.
(ii) It decomposes water very slowly to liberate H2.
(iii) It hardly reacts with bromine while other alkali metals react violently.
(4) Lithium is the only alkali metal which directly reacts with N2 to form lithium nitride (Li3N)
(5) Lithium when heated in NH3 forms amide, Li2NH while other metals form amides, MNH2.
(6) When burnt in air, lithium form Li2O sodium form Na2O and Na2O2 other alkali metals form monoxide, peroxide and superoxide.
(7) Li2O is less basic and less soluble in water than other alkali metals.
(8) LiOH is a weaker base than NaOH or KOH and decomposes on heating.
(9) The ion of Li and its compounds are more heavily hydrated than those of the rest of the group
Hence, option B is correct.
