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7. Elements of group 16,17,18 12

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MHT-CET MCQ Practice Elements of group 16, 17, 18 CET MCQ Chemistry | MHT-CET Previous year questions with detailed solutions MHT-CET 2014 Q1. What is the geometry of a molecule of bromine pentafluoride? (A) Square planar (B) Trigonal bipyramidal (C) Square pyramidal (D) Octahedral Solution: In BrF 5 , the central Bromine atom has 7 valence electrons. It forms 5 sigma bonds with 5 Fluorine atoms. Number of lone pairs = (7 - 5) / 2 = 1 lone pair. Total electron pairs (Steric Number) = 5 (bond pairs) + 1 (lone pair) = 6. The hybridization is sp 3 d 2 . According to VSEPR theory, 6 electron pairs with 1 lone pair results ...
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8. Transition and inner transition element 12th chem CET MCQ

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[2013] 1. Which of the following ion is diamagnetic? (A) Sc 3+ (B) Ni 2+ (C) V 3+ (D) Fe 2+ Correct Answer: (A) Sc 3+ Solution: Sc (Z=21) has the configuration [Ar] 3d¹ 4s². In the +3 oxidation state, it loses 3 electrons to become [Ar] 3d⁰. Since there are no unpaired electrons, it is diamagnetic[cite: 10]. [2014] 2. Select the coloured compound amongst the following. (Atomic no. Ti=22, Cr=24 Cu=29, Zn=30) (A) TiCl 4 (B) CrCl 3 (C) ZnCl 2 (D) CuCl Correct Answer: (B) CrCl 3 Solution: Colour in transition metal compounds is due to d-d transitions[cite: 20]. Cr³⁺ (3d³) has unpaired electrons, making it coloured[cite: 30]. Ti⁴⁺ (3d⁰), Zn²⁺ (3d¹⁰), and Cu⁺ (3d¹⁰) do not have unpaired electrons in the d-subshell. ...
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