用戶【絕命毒師】點評問題和點評內容

【評論主題】19. Which of the following species is paramagnetic in its ground state?(A) (B) CO (C) F2 (D) CN-(E)

【評論內容】這題比前面那題簡單,這題只有E是奇數價電子,且沒有nb電子,一定是順磁。

【評論主題】18. Which of the following element/compound is an p-type semiconductor?(A) Silicon Carbide (B) Diamo

【評論內容】

p-type為雜質半導體extrinsic semiconductor,所以一定是doped,Arsenic不是金屬元素,所以選E

【評論主題】【題組】17. What is the order for the point group of XeF4(A) 10 (B) 12 (C) 14 (D) 16 (E) 18

【評論內容】

算徵表上的對稱操作,公式解法是D4h:D=2,v or h=2,n=4,2x2x4=16

答案為D

【評論主題】【題組】16. Identify the irreducible representation of orbital.(A) (B) (C) (D) (E)

【評論內容】

這題偏難,要想像dxy的形狀,然後以對稱操作看是相反還是沒有,還是他自己,答案為(D)B2g

【評論主題】Questions 15 and 17 are related to the molecule XeF4 and the corresponding character table withhidde

【評論內容】D4h,答案為D,基礎題

【評論主題】【題組】14. How many peaks will you expected from the 'H NMR spectrum for the moleculebicyclo[2.2.2

【評論內容】

只有中間的C和旁邊個方向的碳,兩種,答案為B

【評論主題】Questions 13 and 14 are related to the molecule bicyclo[2.2.2Joctane shown below: 【題組】13. Identify t

【評論內容】

D3h,答案為E,不懂答案要回去看定義,這題很簡單,要秒殺

【評論主題】【題組】12. How many symmetrically independent carbon atom(s) for a molecule?(A) 1 (B) 2 (C) 4 (D) 5 (E)

【評論內容】

i對稱中心,每個碳的化學環境相同。

【評論主題】The questions 11 and 12 are for the molecule Buckminsterfullerene C60 molecule.【題組】11. Identify the

【評論內容】巴克球為高度對稱的Ih,答案為C

【評論主題】10. Identify the crystal system with a ≠ b≠c, a = y =90°, B >90°.(A) Cubic (B) Monoclinic (C) Orthor

【評論內容】

答案為B,這是Monoclinic的定義,後面的不是a跟y,是alpha和gamma還有beta

【評論主題】9.Which of the following element/compound does NOT exhibit a layer structure in the solidstate?(A) C

【評論內容】

問無法結晶的分子,答案為B,氧化的金屬不會結晶。

【評論主題】8.The crystals of CeO2 exhibit a fluorite structure with a coordination number of 4 for the anion.(A

【評論內容】題目不完整,原題目是在說anion陰離子也就是O,一個會有4個配體,那麼cation會有幾個配體,從分子式中可得知Ce:O=1:2,所以一個cation會有8個配體,答案為C

【評論主題】7. Which of the following molecule in liquid form exhibits paramagnetic property?(A) NH3 (B)CO2 (C)O

【評論內容】

這題要以p軌域interaction下去解,排完電子,軌域上有孤電子的為順磁,答案為C

【評論主題】6.Identify the point point group of (A) (B) (C) (D)

【評論內容】

依照價電子我們可以得出這個分子有13個pair而ligand只有3個,只用得到12個pair,所以metal上會有一個lp,sp3為Td型,point group為C3v,答案為B

【評論主題】5.Identify the point group of (A) Td (B) (C) (D) (E)

【評論內容】

依照價電子我們可以得出這個分子有17個pair而ligand只有4個,只用得到16個pair,所以metal上會有一個lp,sp3d為seesaw型,point group為C2v,答案為C

【評論主題】4.Which of the following molecules is the strongest Lewis acid?(A) NF3 (B) SbF5 (C) KCI (D) PCl3 (E)

【評論內容】

Lewis acid 的定義為electronic acceptor,所以越多則酸性越強,而F比Cl酸(記一下),所以答案為B

【評論主題】3.What is the scientific contribution for the 2011 Nobel Laureate Dr. Dan Shechtman?(A) Discovered t

【評論內容】

答案為A,不知道為甚麼考這題,可能想看考生對於時事的關注度吧

【評論主題】2.Which element is in liquid form at T = 50℃(A) Antinomy (B) Gallium (C) Sulfur (D) Carbon (E) Sodiu

【評論內容】

Gallium 鎵的熔點為29.76℃,因此在題目的50℃下為液體(liquid)

【評論主題】1.Modem periodic table is arranged in a sequence based on the property of :(A) Electronegativity (B)

【評論內容】

元素週期表是依照原子數下去做排序的,答案為D