Short Answer Type
Long Answer TypeDiscuss the characteristics of group 13 elements in terms of:
(i) Atomic and ionic radii
(ii) ionisation enthalpy
(iii) Density, melting point and boiling points.
Short Answer TypeLong Answer TypeExplain the following:
(i) Boron is trivalent
(ii) Boron and aluminium tend to form covalent compounds.
Discuss the pattern of variation in the oxidation states of B(Boron) to Tl(Thallium).
Or
What is inert pair effect? Illustrate it with reference to Boron family.
Short Answer TypeStandard electrode potential values 
and that of 
is +1.26 V. Predict about the formation of M3+ ion in solution and compare the electropositive character of the two metals.
What are electron deficient compounds? Is BCl3 electron deficient species?
Species in which the central atom either does not have eight electrons in the valence shell or those which have 8 electrons in the valence shell but can expand their covalency beyond 4 due to the presence of d-orbitals are called electron deficient molecules.
BCl3 is an electron deficient compound because the central boron atom has only six electrons. As a result, it accepts a pair of electrons from NH3 to form an adduct.
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