25. In β-Hydrogen elimination, the following are true except: [2 pts]
(A)The metal center must have 18 valence electrons
(B) The metal center must have a vacant site
(C) There must be a hydrogen atom at the B position
(D) The M-C-C-H unit must be able to achicve coplanarity
(E) None of above is correct

21. N2 can act as a ligand in a similar way as CO. In comparison to CO, which of the following is true?[2 pts] (A)It is a better σ donor and i acceptor. (B) It is a better σ donor but poorer tt acceptor. (C) It is a poorer σ donor but a better x acceptor. (D) It is a poorer σ donor and it acceptor. (E) None of above is correct

22. Which of the following diphosphine is BINAP? (BINAP = 2,2-bis(diphenylphosphino)-1, 1'-binaphthy) [2 pts] (A)1 (B)2 (C) 3 (D) 4

23. One of the following complexes does not contain a dihydrogen ligand. Which is likely? (note: dppe = 1,2-bis(diphenylphosphino)ethane; Ph = phenyl;iPr = isopropyl) [2 pts] (A)MoH2(CO)(dppe)2 (B) WH2(CO)(dppe)2 (C) RuH4(PPh3)3 (D) [ReH2(PiPr3)3(CO)3]+

24. The primary decomposition pathway for transition metal alkyls is: [2 pts] (A)a-Hydrogen elimination (B) B-Hydrogen elimination (C) v-Hydrogen elimination (D) Reductive elimination (E) Oxidation addition

26 Which of the following geometry isomers is correct?[2 pts] (A) I (B) II (C) III (D)IV

27. What are the ALL possible magnetic moments of Co(Il) in tetrahedral, octahedral, and square-planar complexes? [2 pts] I. Co(Ⅱ) is d7. Il. In tetrahedral complexes, it is generally high spin and has 3 unpaired electrons;Ⅲ. In octahedral complexes, it is also typically high spin and also has 3 unpaired electrons; in square planar complexes, it has 1 unpaired electron. IV. The magnctic moments can be calculated as μ = n(h+1) = 3.9, 3.9, and 1.6 mB, respectively. (A) I, II (B) I, II, II (C) I, II, II, IV (D) II, II, IV

28. Which of the following spin arrangement is NOT correct? [2 pts] (A) II, II(B) I, III (C) I, IV (D) II, IV 

29. NF is a known molecule.Which of the following description is correct? [2 pts] (A) I, II, Ⅲ (B) II, III, IV (C) I, III, IV (D) I, II, IV

30. Predict the products of these reactions [2 pts]I. (a) is cis-[PtCl2(NO2)(NH3)]- II. (b) is trans-[PtCI(NO2)2(NH3)]-III. CI- has a larger trans effect than NH3, but smaller trans influence than NH3IV. NO2- has a larger trans effect than either Cl- or NH3. (A) I and II (B) I, II, III (C) I, I, IV (D) I, I, II, and IV III. IV.

1.請問蛋白質的二級結構是由何種力或鍵結構成: (A)氫鍵 (B)凡得瓦力 (C)親水疏水力 (D)庫倫力