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What is different between elements of first group and other group is s and p-block? Why? |
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Answer» Solution :Behaviour of first group of elements are different from other elements because their volume are very less and charge or radius are high and more electronegativity. (i)Metallic radius are less : Ex. Metallic radius of first group of elements M/pm : Li (152) , Be(111) , B (88) Metallic radius of second group of elements M/pm : Na (186) , Mg (160) , Al (143) (II) Ionic radius are less : Ionic radius of first group of elements M+/pm : Li (76), Be (31) Ionic radius of second group of elements `M^(+)`/pm : Na (102), Mg (72) Maximum four valence orbitals are form in bond FORMATION `(2s, 2p_(x) , 2p_(y), 2p_(z))`. vailable for bonding, whereas the second member of the groups have nine valence orbitals `(3s , 3p , 3d)`. As a consequence of this, the maximum covalency of the first member of each group is 4 (e.g., boron can only form `[BF_(4)]^(-)` , whereas the other members of the groups can expand their valence shell to accommodate more than four pairs of electrons (e.g. aluminium forms `[AIF_(6)]^(3-)`). Furthermore, the first member of p-block elements displays greater ability to form `p_(pi) - p_(pi)`multiple bonds to itself. e.g. : `C = C, -= C, N = N , N -= N` First member from `p_(pi) - p_(pi)`bond with other elements of second PERIOD. While other elements of group do not form `p_(pi) - p_(pi)` bond. |
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