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And one thing I want to tell you to start out with is something about this c h 3 group here.
有一点需要告诉大家的是,从这个一个碳原子和三个氢原子的组合开始。
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The other chain is facing in the other direction, the 3' carbon is up, the 5' carbon is down.
对面的那条单链方向相反,3'位的碳原子向上,5'位的碳原子向下
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So in terms of the first step of skeletal structure, this is actually going to be easier because we don't have a central atom, we just have carbon and nitrogen here.
对于第一步画出骨架，其实比刚才更容易,因为我们没有一个中心原子，我们这里只有碳和氮两个原子。
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The electrons are not equally shared and the carbon hogs the electrons a little bit more than the hydrogen, so the carbon is electron-rich and the hydrogen is just a little bit electron-deficient.
电子不是平均共享的,碳原子比氢原子吸引电子,更强烈一点点，所以碳原子是富电子,而氢原子是缺电子。
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And you might have kind of been projecting ahead and thinking if we keep up at this pace, pretty much we would only get to carbon by the end of the semester.
你们可能会有这种推测：,如果我们以这个速度继续下去的话，这个学期,也只能讲到碳原子。
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So let's take the case of acetylene where we have two carbon atoms that are going to be triple bonded to each other, each are bonded to a carbon and then to one hydrogen.
让我们来看一看乙炔的例子,我们有两个碳原子,成三键，每个碳和一个碳一个氢相连。
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So, why don't you go ahead and tell me, keeping that in mind, which atom in terms of h c or n would you expect to be in the center of hydrogen cyanide?
那么，请大家来告诉我，并且记住它，你认为氢，碳和氮中哪个原子,应该在氰化氢的中间呢？
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I'm an organic chemist, so I love carbon, it's one of my favorite atoms to talk about, but it would be nice to get to the point of bonding and even reactions to talk about all the exciting things we can think about once we're at that point.
我是个有机化学家，我喜欢碳原子，这是我最喜欢谈论的原子之一，但我更喜欢讲成键,甚至化学反应的概念,一旦到了这之后,我们就可以考虑各种激动人心的事情。
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Benzene is a ring that's made up of six carbon atoms and six hydrogen atoms.
苯环是一个由六个碳原子,和六个氢原子组成的环。
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PROFESSOR: All right, start again, what's the hybridization of the carbon atom?
好了，再说一遍，碳原子的杂化轨道是什么？
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If we think about bringing in those last two carbons, what you can see is that for every carbon, two of its hybrid orbitals are being used to bond to other carbons.
如果我们考虑引入最后两个碳原子，你会看到的是对于每个碳原子，其中的两个杂化轨道,和另外的碳原子成键。
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They'd like to be able to refer to each carbon separately so they can talk about reactions with this molecule, so they number the carbons.
为了在探讨这种大分子的,化学反应时能清楚地,表示每一个碳原子,人们对碳原子进行了编号
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And this is really good news because it's good to get passed carbon.
可以讲到碳原子,是个好消息。
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I would attach the phosphate that's connected to the 5' carbon of another nucleotide.
我会添加一个磷酸基团到,另外一个核苷酸的5'碳原子上
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sp3 PROFESSOR: OK, so it's 2 s p 3, and our second carbon is also 2 s p 3.
好的，是，第二个碳原子也是2sp3。
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then what you have is a carbon in the middle with three hydrogens around it, and then it can only be bonded to one other thing.
那么你就会有一个碳原子在中心,三个氢原子围绕着它，那么它只能再和一个原子成键。
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So our skeleton tells us that carbon is in the middle, so we'll put the h on one side, and the n on the other side there.
我们的骨架告诉我们碳原子应该放在中间，因此我们把氢原子放在一边，把氮原子放在另外一边。
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So, if we want to figure out the formal charge on the carbon, we need to take the number of valence electrons, so that's 4. We need to subtract the lone pair, what number is that? It's 2.
如果我们想算出碳原子的形式电荷，我们需要将价电子的个数，也就是四，减去孤对电子的个数，它是多少？是二。
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Can we have one between these two carbons here if we have one here?
这两个碳原子之间能有吗？,如果我们有一个？
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So again, if we think about that shape of that carbon atom, it's going to be trigonal planar, 120° it's going to have bond angles of 120 degrees, because we have this set up of having three hybrid orbitals.
如果我们考虑碳原子的形状，它是平面三角形，键角是，因为我们有这三个杂化轨道。
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So that leaves each carbon with only one hybrid orbital left.
这样每个碳原子只剩下一个杂化轨道。
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And so you can look, for example, at the Periodic Table And, if you look up the atomic mass of carbon, 011 you will see that carbon comes at 12.011 for carbon.
如你们所见，例如，在周期表中,如果你观察碳的原子质量，你会看到是12。
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So most of you saw that carbon should be in the center.
看来大部分人都知道碳原子应该在中间。
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The phosphate is linked to this carbon on the pentose, and notice that there is a number on this carbon, it's called - it's the 5' carbon.
磷酸基连接在戊糖的一个碳原子上,注意在这个碳上有个数字,它叫做5'碳
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these pentose molecules, whether it's ribose or deoxyribose, the carbons are numbered the same 1', 2', 3', 4', 5', those are the five carbons that make up the pentose.
这些戊糖分子,不管是核糖还是脱氧核糖,碳都是从1'标注到5',也就是构成戊糖的5个碳原子
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So let's take a look at this with carbon.
让我们看一下这个碳原子。
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It wouldn't be the same if I turned it upside down because the carbons - the rings here, the pentose's would all be turned over, the chemistry would look different and the sequence of bases would look different.
记住单链倒过来,就和原来不一样了,这是因为碳原子和糖环结构,戊糖会翻转,使得这个化学结构看起来不一样了,碱基的顺序也不一样了
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So, what we end up having is three of these pi -- 2 p y 2 p y bonds, we can have one between these two carbons here.
我们剩下的有三个π键-,2py2py键，在这两个碳原子之间会有一个。
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So if you picture this as our s p 2 carbon atom where we have three hybrid orbitals, and then one p y orbital coming right out at us.
如果你把这想象成sp2碳原子,这里有3个杂化轨道，然后一个py轨道朝向我们。
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And then we're going to name the atomic orbitals that make it up, and it's being made up of a carbon 2 s p 3 orbital, and a hydrogen 1 s orbital.
然后我们要命名,组成它的原子轨道，它是由碳2sp3轨道，和氢原子1s轨道组成。
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