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प्रश्न
Describe the general trends in the following properties of the elements in Groups 13 and 14.
Atomic size
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उत्तर
Grp-13 The atomic size of the boron family follows the irregular trend. Generally, down the group the size increases but Gallium has a smaller atomic radius than Aluminium due to the poor shielding effect of 3d-orbitals.
Order: B < Ga < Al < In < Ti
Grp-14 The size of the carbon family is smaller than the modern family and as we move down the group the atomic size increases regularly. The increase in covalent radius from carbon to silicon is prominent while from Silicon to lead a small increase in covalent radius is observed; this is due to the presence of completely filled D and f-orbital in the heavier members.
Order: C < Si < Ge < Sn < Pb
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संबंधित प्रश्न
Suggest reasons why the B–F bond lengths in BF3 (130 pm) and `"BF"_4^(-)` (143 pm) differ.
What happens when BF3 is reacted with ammonia?
In some of the reactions thallium resembles aluminium, whereas in others it resembles with group I metals. Support this statement by giving some evidences.
Write a balanced equation for B2H6 + NH3 → ?
The most commonly used reducing agent is ______.
Which of the following statements are correct. Answer on the basis of Figure.
(i) The two birdged hydrogen atoms and the two boron atoms lie in one plane;
(ii) Out of six B – H bonds two bonds can be described in terms of 3 centre 2-electron bonds.
(iii) Out of six B – H bonds four B – H bonds can be described in terms of 3 centre 2 electron bonds;
(iv) The four-terminal B – H bonds are two centre-two electron regular bonds.
Explain why the following compounds behave as Lewis acids?
BCl3
Aluminium dissolves in mineral acids and aqueous alkalies and thus shows amphoteric character. A piece of aluminium foil is treated with dilute hydrochloric acid or dilute sodium hydroxide solution in a test tube and on bringing a burning matchstick near the mouth of the test tube, a pop sound indicates the evolution of hydrogen gas. The same activity when performed with concentrated nitric acid, reaction doesn’t proceed. Explain the reason.
Explain the following:
Boron does not exist as B3+ ion.
Explain the following:
PbX2 is more stable than PbX4.
Explain the following:
Pb4+ acts as an oxidising agent but Sn2+ acts as a reducing agent.
Identify the compounds A, X and Z in the following reactions:
\[\ce{A + 2HCl + 5H2O -> 2NaCl + X}\]
Match the species given in Column I with the properties mentioned in Column II.
| Column I | Column II |
| (i) \[\ce{BF^{-}4}\] | (a) Oxidation state of central atom is +4 |
| (ii) AICI3 | (b) Strong oxidising agent |
| (iii) SnO | (c) Lewis acid |
| (iv) PbO2 | (d) Can be further oxidised |
| (e) Tetrahedral shape |
Match the species given in Column I with properties given in Column II.
| Column I | Column II |
| (i) Diborane | (a) Used as a flux for soldering metals |
| (ii) Galluim | (b) Crystalline form of silica |
| (iii) Borax | (c) Banana bonds |
| (iv) Aluminosilicate | (d) Low melting, high boiling, useful for measuring high temperatures |
| (v) Quartz | (e) Used as catalyst in petrochemical industries |
Describe the general trends in the following properties of the elements in Groups 13 and 14.
Oxidation states
Account for the following observations:
Though fluorine is more electronegative than chlorine yet BF3 is a weaker Lewis acid than BCl3
Account for the following observations:
PbO2 is a stronger oxidising agent than SnO2
Boron compounds behave as Lewis acids because of their ______.
A group 13 element ‘X’ reacts with chlorine gas to produce a compound XCl3. XCl3 is electron deficient and easily reacts with NH3 to form \[\ce{Cl3X –> NH3}\] adduct; however, XCl3 does not dimerize X is ______.
