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if we're actually thinking about electron configuration and we look at lithium, sodium and potassium, these all have one valence electron.
让我们来想一想,锂，钠，钾的电子排布，它们都只有一个价电子。
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So we could think about comparing the potassium ion to a sodium ion. They have the same charge of plus one.
我们可以想象比较一下钾离子,与钠离子，它们都同样带有正一价的电荷。
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The ones that are most important in physiology are ones that only allow ions to go through: sodium, potassium, chloride, calcium, bicarbonate.
在生理学上这种,只能允许某种离子通过的通道十分重要,这些离子包括钠离子,钾离子,氯离子,钙离子和碳酸氢根离子
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And I say, no, I think any of you should know that potassium lies under sodium.
我要说的是，你们应该知道,钾是在钠的下面的。
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They would be things like calcium phosphorous, potassium, sodium, etc.
比如钙,磷,钾,钠等等这些
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And actually, a question that might come up, I just explained, the sodium channel, you might say, well, how do potassium channels work then, because I can understand how you can filter something big out, but how do you filter out something small.
实际上，可能大家会问一个问题，我刚解释过，钠离子通道，你可以说，好吧，那么钾离子通道该如何起作用呢，因为我可以理解你是如何把大东西过滤掉的，但是你如何把小东西过滤掉呢？
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And they wanted to use a soluble salt of citric acid, so they could have used sodium, they could have used potassium.
而且他们想用一种柠檬酸的可溶性盐，他们本可以用钠，也可以用钾。
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Similarly, we find it in table salt, we're taking it in all the time, the same with potassium, think of bananas, were always eating potassium.
同样地，我们发现食盐中含有钠，而我们一直在吃盐，钾也一样，想一想香蕉吧，吃香蕉也就是在吃钾。
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He said look at sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium.
他说，看，钠，镁，铝，硅，磷，硫磺，氯，钾。
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In addition, the kidney controls the composition of your body of many important ions, sodium bicarbonate which is important in pH balance, potassium.
此外肾脏还能控制,体内很多重要离子的浓度,例如碳酸氢钠,它对于酸碱平衡十分重要,还有钾离子
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That potential difference is generated by the movement of ions, principally sodium and potassium across the membrane.
电势差是由离子运动造成的,特别是钠和钾的跨膜运动
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So, again, it is based on size, it's a little bit less intuitive than the idea of just straining out all of the potassium ions.
因此，这还是以尺寸为基础的，只是有点不够直观,与钾离子挤不进去的图像相比。
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The only thing that's different is that they're one down on the periodic table, potassium is down one row, so it's going to be a little bigger, but when we're thinking about size, it maybe does not seem that significant to talk about the size.
它们唯一的不同点,就在于其中一个在周期表的下面，钾在下一行，因此它要稍微大一些，但是当我们考虑尺寸的时候，似乎讨论尺寸的意义不大。
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Potassium lies one octave from sodium.
钾与钠隔着一个八度。
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All cell membranes have these channels within them, and under their resting conditions sodium is moving from outside to inside, potassium's moving from inside to outside.
所有细胞膜上都有这种通道结构,在静息状态下,钠从细胞外流向细胞内,钾从细胞内流向细胞外
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s1 So for the fourth period, now we're into the 4 s 1 3d for potassium here. And what we notice when we get to the third element in 4s2 and the fourth period is 3d that we go 4 s 2 and then we're back to the 3 d's.
对于第四周期到现在我们来到钾的1,然后我们返回到,我们注意到当我们看到第三个元素,第四周期我们来到,然后我们返回到。
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And that's all that's big enough to pass through or small enough to pass through. And if we go up even just one row on the periodic table to potassium, what we actually see is now that it's going to be too large, and, in fact, a potassium solvated with one water molecule won't go through our channel.
就是这样刚好大到它通过,或者说刚好小到它通过,即使我们再沿着周期表往下走仅仅一行到钾离子，我们看到的就将是它的个头太大了，实际上，溶解于一个水分子的单个钾离子,不能穿过我们的通道。
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So, for example, here we're showing rubidium and potassium and sodium plotted where we're plotting the frequency -- that's the frequency of that light that's coming into the metal versus the kinetic energy of the electron that's ejected from the surface of the metal.
让大家看来都是可以理解的事情,就是把不同金属的观测结果,画到一张图里面来，例如这里,我们展示的是钠，钾,铷的频率-这是照射金属的光的频率,和金属表面出射电子动能的关系。
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The balance of sodium movement relative to potassium movement changes because there's this resting movement of all these molecules anyway, but that balance changes dramatically when these ion - when these gated ion channels open.
钠钾各自运动始终保持动态的平衡,因为尽管在静息状态,所有这些离子也在运动,但是平衡的剧烈变化,只发生在这些门控离子通道打开的时侯
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Now, it's more complicated than that because it's not just sodium channels that are involved, there are potassium channels also, and the interplay between sodium channels opening and potassium channels opening, this is described in some detail in your book.
现在 事情更复杂了,因为这一过程不仅关系着钠离子通道,也关系着钾离子通道,以及钠离子通道和钾离子通道之间开关,的相互作用,书中有详细解释
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Now, sodium and potassium don't ordinarily move across membranes, they're charged molecules, they can't dissolve, they can't permeate through a cell membrane, but they go through because there are channels that allow them to pass through in the membrane.
钠和钾通常是不能跨过细胞膜的,它们都是带电粒子,它们不能溶解在细胞膜中,不能渗透通过细胞膜,但它们之所以能通过细胞膜,全赖膜上离子通道的作用
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So if we consider lithium, potassium, and sodium, they're all together in the same group on the periodic table, knowing what we do about biology we can immediately think of sodium and potassium, or even just knowing what you know about table salt, for example, that these are two elements that we find, and particularly in the ion form in very high concentrations in our body.
我们来考虑一下锂，钾和钠，它们都在周期表中的同一族里，想要知道我们将元素周期律,用到生物学会怎么样，我们首先想到的就是钠和钾，甚至只需要知道食盐，我们发现它们是以很高浓度的离子形式,存在于我们体内的两种元素。
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So what we know is that these 3 d orbitals are higher in energy than 4 s orbitals, so I've written the energy of the orbital here for potassium and for calcium.
我们所知道的是,3d轨道能量,比4s轨道能量高，所以我写出了,钾和钙的轨道能量。
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Potassium is 4s, and I've only finished with 3p.
钾是4s电子，我只完成了3p轨道排布。
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