18 - A unit cell of ReO3 consists of a cubic arrangement of Re atoms with O atoms centred along each edge of the cube. What is the coordination number of each Re atom? 20 - Which of the following is the correct electron configuration for Cut2? A) [Ar] 45 3d 10 B) [Ar] 4s 3d 10 C) [Ar] 45 3d9 a) 6 b)3 c) 1 d) 8 e) 4 D) [Ar] 452 3d E) [Ar] 4s 3d a) OC 21 - In terms of hard-soft acid-base theory, which of the following is true for end of the SCN- anion would and indicate the hardest one. 22 - In what order is the increase in both gas phase and aqueous basicity correct? W. hardest a) 0,3 b) Pel- c) 03. W. hardest S. hardest a)NH2Et2 NHEL2 > NH2Me NHMe2 > NH3 NHBu 2 b) O NH3 NHMe > NHMen > NHEt2 NH2E NHBu2 d) NH3 - NHBU 2-NH2MeNH2E NHMe2 NHET2 e) NHB2 Nity NHMe 2 N7t N We 13 d) Ag N hardest e) P42-8. hardest Bos birak n-- I.....I. 24 - Which structure of SCN is most stable? 23 - What is the molecular shape around iodine atom in iodine trifluoride? a) T-shaped b) Trigonal planar a) S-C=N b) S-N-C - SNC d) S=C-N e) S-CEN Bo brak C) Tetrahedral d) See saw e) Trigenal pyramid