团队作业第三组3. 分子间作用力定 义:分子间作用力产生在不同的分子之间,以离子键、氢键、偶极-偶极相互作用和范德华力形式存在。作用力的类型取决于存在的官能团。离子键: 羧基和氨基这样的可离子化官能团之间可能存在离子键。氢 键: 醇、羧酸、酰胺和酚可能产生分子间氢键,因为这些官能团含有与氮或氧键合的氢原子。氢键指一个分子的带有部分正电荷的氢原子与另一个分子带有部分负电荷的杂原子间的相互作用。氮和氧以外的元素也可能形成氢键。范德华力:范德华力是指具有瞬间正负电荷区域的不同分子的弱相互作用力。这种瞬间电荷是由电子的无规波动引起的,烷烃,烯烃,炔烃和芳环之间可以通过范德华力而相互作用。
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团队作业第二组2. 共价和杂化共价键: 两个氢原子彼此靠近时,它们的1s原子轨道相互作用形成一个成键和一个反键轨道(MO)。当1对电子填充到成键中且反键轨道为空轨道时,便形成一根稳定的共价键。σ 键: 两个原子轨道头对头重叠形成一个横截面为圆形的键,即为σ键,σ键是一种强键。杂化: 碳原子的电子排布意味着碳应该形成2根键。然而,众所周知碳生成的是4根键。在有机结构中,它可以通过被称之为杂化的过程,“混合”价层的2s 和2p轨道。3种可能的杂化方式为:sp3,sp2和sp杂化。
团队作业第一组1. 碳原子的结构原子轨道: 碳原子有6个可占用的原子轨道,即第一层的s轨道,第二层的s轨道和3个p轨道。1s和2s轨道是球形的。2p轨道呈哑铃形,根据它们的取向可以区分为2px,2py和2pz轨道。能 级: 1s轨道的能量低于2s轨道,而2s轨道的能量低于2p轨道。2p轨道能级相同(它们是简并轨道)。电子排布: 碳位于周期表第二周期,其6个电子在进入较高能级轨道之前首先填充较低能级的原子轨道(能量最低原理)。每个轨道最多可容纳2个自旋相反的电子(泡利(Pauli)不相容原理)。如果轨道的能级相同,电子将占据尽可能多的轨道(洪德(Hund)规则)。因此,碳原子的电子排布为1s22s22px12py1。
Dialogue OneInterviewer: Good morning.Applicant: Good morning. I’m Yang Hai. I’ve come for (1)as requested.Interviewer: Oh, yes. We have received your letter and resume. Have you (2)in advertising?Applicant: Yes, I’ve been working in an advertising firm for three years.Interviewer: (3)to leave your previous job?Applicant: I want to broaden my experience and improve my position.Interviewer: Why do you (4)Applicant: Because your company is one of the largest and best firms in (5). It’s very helpful to the further development of my abilities.Interviewer: Then what is your (6)?Applicant: As to the salary, I leave it to you. I believe you must have a standard starting salary, which should be satisfactory.Interviewer: (7), the starting salary is not high. But if you do well, we’ll give you raises.Applicant: I see. When can I know whether I’m accepted or not?Interviewer: Next Friday (8)
Interviewer: Do you want a (1)or a part-time job?Applicant: A part-time job. I have to (2)Interviewer: Do you mind working on (3)?Applicant: Not at all. Because I have to study during the day.Interviewer: Very well. The night shift is from 6 p.m. to 12 p.m. Then, what is the(4)you may consider?Applicant: Twenty yuan per hour.Interviewer: It’s a deal. When can you (5)?Applicant: I can start anytime.Interviewer: Good. You can come tomorrow evening.Applicant: Thank you very much. See you tomorrow.Interviewer: See you.