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Online class 1, , UNIT 8, , d-BLOCK & f-BLOCK ELEMENTS, , , , SECTION 1-d BLOCK ELEMENTS, , d-block elements can be defined as the elements which have, partially filled d-orbitals. In the periodic table group 3 to group, 12 belongs to d-block. d-block elements are otherwise called, transition elements because properties like electronegativity,, electropositivity, atomic size, metallic character etc changes, through d-block elements., , GENERAL PROPERTIES OF d-BLOCK ELEMENTS., , , , 1., , ELECTRONIC CONFIGURATION, , The general outer electronic configuration of d-block, elements is ns’? (n-1) dd‘., , . ELECTRONIC CONFIGURATION OF IONS, , Write the electronic configuration of the following ions., , Fe* Sc** Zn, Cu, Cr, Mn 2*., , . COLOUR, , » Majority of d-block elements form-coloured ions., , » This is due to d-d transition. d-d transition is possible, only if the ion is having partially filled d-orbital., , Classify the following ions into coloured and colourless., Sc 3+, Zn2+, Mn2+, Fe 3+ , Cu +, Cu 2+, Ti 4+., , . MAGNETIC PROPERTIES, , » Majority of transition metal ions are paramagnetic., , Edit with WPS Office

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This is because, majority of d-block metal ions, contain unpaired electrons., , » Paramagnetism can be expressed in terms of, magnetic moment which can be calculated ‘spin only’, formula., , y= _/n(n+2) BM, where n-number of unpaired electrons., , BM-Bohr magneton (unit of magnetic, moment), , » The above equation is called spin only formula, because magnetic moment due to spin motion of, unpaired electron is considered in the above, equation and magnetic moment due to orbital, motion of the electron is neglected., , > Different p values (in BM) corresponding to different, n values are,, , , , , , , , , , , , , , n, 0, 1 [17, 2 | 28, 3 | 38, , | 4 | 49 |, 5 | 5.9, , , , , , , , , , QUESTIONS, , Edit with WPS Office

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. Calculate the magnetic moment of a divalent ion, in aqueous solution if its atomic number is 25., , Ans. Electronic configuration of atom 4s2 3d5, , Configuration of divalent ion 4s0 3d5, , , , TET) Tt] ty t, , , , , , , , , , , , , , , , So, n=5, u=5.9 BM, , . Calculate spin only magnetic moment of M2+ ion, (Z=27) ---HOME WORK. (Ans. 3.8), , 4/4 Edit with WPS Office