this is how the most revolutionary course in biology of all time begins.

這就是有史以來最具革命性的生物學課程的開始。

Come today to learn about covalent and ionic and hydrogen bonds

今天就來學習一下共價鍵和離子鍵以及氫鍵的知識。

What about electron orbitals

那電子軌道呢

and the octet rule

和八位數規則

and what does it all have to do with a mad man named Gilbert Lewis?

這一切和一個叫吉爾伯特-劉易斯的瘋子有什麼關係？

It's all contained within.

它'都包含在裡面。

Hello, I’m Hank

你好，我是漢克

I assume you’re here because you’re interested in biology

我想你來這裡是因為你對生物學感興趣吧？

and if you are, that makes sense because

如果你是，這是有道理的，因為

like any good 50 Cent song, biology is just about sex and not dying.

就像任何一首好的50美分的歌一樣，生物學只是關於性和不死。

Everyone watching this should be interested in sex and not dying

大家看這個應該是對性有興趣，而不是死亡

being that you are, I assume, a human being.

我想，你是一個人。

I'm going to be teaching this biology course differently than most courses you've ever

我將以不同於大多數課程的方式來教授這門生物課

taken in your life

生前

For example, I'm not going to spend the first class

比如說，我'不打算花頭等艙

talking about how I’m going to spend the rest of class.

談論我將如何度過剩下的課時。

I'm just going to start teaching you, like right about now.

我'我只是要開始教你，就像現在。

I may say one more thing before I start teaching.

在開始教學之前，我可以多說一句。

Yes, I am going to!

是的，我要去！

It's that: if I’m going too fast for you, the great thing about YouTube is

它'是：如果我對你來說太快了，YouTube最大的好處是。

that you can just rewind.

你可以只是倒帶。

Watch stuff over and over again if it's confusing.

看東西一遍又一遍，如果它是混亂的'。

Hopefully, it will become less confusing.

希望能變得不那麼混亂。

And you're even allowed to fast forward through the bits that you already know.

而且你甚至可以快進你已經知道的部分。

Another tip, you can actually even use the number keys on your keyboard to move around

還有一個小竅門，其實你甚至可以用鍵盤上的數字鍵來移動。

in the video.

在視頻中。

And I promise, you can do this to me as much as you want and I'm totally not going to mind.

我保證，你可以盡情地對我做這個，我完全不會介意。

A great professor of mine once told me that in order to really understand any topic

我的一個偉大的教授曾經告訴我，為了真正理解任何主題

you have to understand a little bit of the level of complexity just below that topic.

你要了解一下這個話題下面的複雜程度。

The level of complexity just below biology is chemistry

複雜程度僅次於生物學的是化學。

unless you're a biochemist in which case you would argue that it's biochemistry.

除非你'是一個生物化學家，在這種情況下，你會認為它'的生物化學。

Either way, we're gonna have to know a little bit of chemistry in order to get through biology.

不管是哪種方式，我們'都要懂得一點化學知識，才能通過生物學。

And so THAT, my friends, is where we're going to start.

所以，我的朋友們，這就是我們要開始的地方'。

I am a collection of organic molecules called Hank Green.

我是一個有機分子的集合體，叫漢克-格林。

Organic compounds are a class of compounds that contain carbon.

有機化合物是一類含碳的化合物。

And carbon is this sexy little minx on the periodic table

而碳是元素週期表上這個性感的小東西

that's, you know...

那是，你知道... ...

disinterested in monogamy.

對一夫一妻制不感興趣。

A jezebel. Bit of a tramp. Hussy.

一個Jezebel。位的流浪漢。婊子。

When I say carbon is small I mean that it's actually

當我說碳是小的時候，我的意思是它實際上是

as an atom, it's a relatively small atom.

作為一個原子，它是一個比較小的原子。

It has 6 protons and 6 neutrons for a total atomic weight of 12.

它有6個質子和6箇中子，總原子量為12。

Because of that, carbon doesn't take up a lot of space.

正因為如此，碳不會佔用很多空間。

And so carbon can form itself into weird rings, and sheets and spirals

所以碳可以形成奇怪的環、片和螺旋狀的東西

and double and even triple bonds.

和雙倍甚至三倍的債券。

It can do all sorts of things that could never be accomplished by more bulky atoms.

它可以做各種更笨重的原子所無法完成的事情。

It's basically, your atomic equivalent of an olympic gymnast.

它基本上，你的原子相當於奧運體操運動員。

It can only do all of those wonderful, beautiful, elegant things because it's kind of tiny.

它只能做到所有這些美妙、美麗、優雅的事情，因為它'的那種微小。

It's also said that carbon is kind

也有人說，碳是一種。

and that's an interesting sort of thing to say about an atom.

這對原子來說是件很有趣的事情。

It's not like some other elements that are just

它不像其他一些元素，只是。

desperately trying to do anything they can

竭盡全力

to fill up their electron orbitals.

以填補其電子軌道。

No, carbon knows what it's like to be alone, and so it's not all

不，碳知道孤獨的感覺，所以並不是所有的人都知道

“Please! I'll do anything for your electrons!”

"求求你了!我願意為你的電子做任何事情！"

needy like fluorine or chlorine or sodium is.

像氟或氯或鈉一樣需要。

Elements like chlorine if you breath them in they like literally tear up your insides

像氯這樣的元素，如果你把它們吸入體內，它們就會把你的內臟撕碎。

and sodium, sodium is insane if you put it in water it explodes!

和鈉，鈉是瘋狂的如果你把它放在水裡就會爆炸!

Carbon though...

碳雖然...

Meh.

呵。

It wants more electrons, but it's not gonna kill to get them.

它想要更多的電子，但它不會為了得到電子而殺人。

It makes and breaks bonds like a 13-year old mall rat.

它像13年的商場老鼠一樣製造和破壞債券。

And it doesn't even hold a grudge.

而且它甚至不記仇。

Carbon is also, as I mentioned before, a bit of a tramp, because, it needs four extra electrons

正如我之前提到的，碳也是一個有點流浪的東西，因為，它需要額外的四個電子。

and so it'll bond with pretty much whoever happens to be nearby

所以它會與幾乎所有碰巧在附近的人建立聯繫。

And also because it needs four electrons, it'll bond with two, or three

也因為它需要4個電子，所以它會和兩個，或者三個電子結合在一起。

or even four of those things at the same time

乃至四種以上

And carbon is willing and interested to bond with lots of different molecules

而碳是願意並有興趣與很多不同的分子結合的。

like hydrogen, oxygen, phosphorous, nitrogen

如氫、氧、磷、氮

or to other molecules of carbon.

或對其他碳分子。

It can do this in infinite configurations

它可以在無限的配置中做到這一點

allowing it to be the core atom of complicated structures that make living things like ourselves

讓它成為複雜結構的核心原子，使我們這樣的生物得以生存

because carbon is this perfect mix of small, kind, and a little bit trampy

因為碳是這個完美的組合 小巧，善良，和一點點躑躅不前。

life is entirely based on this element.

生活完全是基於這個因素。

Carbon is the foundation of biology.

碳是生物的基礎。

It's so fundamental that scientists have a pretty difficult time

它是如此的基本，以至於科學家們相當困難。

even conceiving of life that isn't based on carbon.

甚至設想生命是不是基於碳。

Life is only possible on earth because carbon is always floating around in our atmosphere

只有地球上的生命才有可能，因為碳總是漂浮在我們的大氣層中。

in the form of carbon dioxide.

以二氧化碳的形式存在。

So it's important to note, when I talk about carbon bonding with other elements

所以要注意的是，當我說到碳與其他元素的結合時，很重要的一點是

I'm not actually talking about sex, it's just a useful analogy.

我'其實不是在說性，這只是一個有用的比喻。

Carbon, on it's own, is an atom with 6 protons, 6 neutrons, and 6 electrons.

碳，就其本身而言，是一個有6個質子、6箇中子和6個電子的原子。

Atoms, have electron shells, and they need to have these shells filled

原子，有電子殼，它們需要有這些電子殼的填充。

in order to be happy, fulfilled atoms.

才能成為快樂、滿足的原子。

So carbon, has 6 total electrons, 2 for the first shell

所以碳，共有6個電子，其中2個是第一殼的電子

so it's totally happy

所以它完全快樂

and 4 of the 8 it needs to fill the second shell.

和8箇中的4個，它需要填補第二個殼。

Carbon forms a type of bond that we call covalent.

碳形成的一種鍵，我們稱之為共價鍵。

This is when atoms actually are sharing electrons with each other.

這時，原子之間實際上是在互相分享電子。

So in the case of methane, which is pretty much the simplest carbon compound ever.

所以在甲烷的情況下，這幾乎是有史以來最簡單的碳化合物。

Carbon is sharing it's 4 electrons, in it's outer electron shell, with 4 atoms of hydrogen.

碳是分享它的4個電子，在它'的外層電子殼，與4個氫原子。

Hydrogen atoms only have 1 electron, so they want their first S orbital filled.

氫原子只有1個電子，所以它們希望自己的第一個S軌道被填滿。

Carbon shares its 4 electrons with those 4 hydrogens

碳與這4個氫共享4個電子。

and those 4 hydrogens each share 1 electron with carbon.

而這4個氫與碳各共享1個電子。

So everybody's happy.

所以大家都很高興。

In chemistry and biology this is often represented by what we call Lewis dot structures.

在化學和生物學中，這通常用我們所說的劉易斯點結構來表示。

Good lord, I'm in a chair!

天啊，我坐在椅子上了!

I'm in a chair and there's a book.

我'在椅子上，有'的書。

Apparently I have something to tell you that's in this book.

顯然，我有話要告訴你，'在這本書裡。

Which is a book called Lewis: Acids and Bases.

這是一本叫劉易斯的書。酸和鹼。

By Hank Green

作者：漢克-格林

Gilbert Lewis, the guy who thought up Lewis dot structures

吉爾伯特-劉易斯，想出劉易斯點陣結構的人

was also the guy behind Lewis Acids and Bases

也是劉易斯酸和鹼的幕後推手。

and he was nominated for the nobel prize

他被提名為諾貝爾獎得主

35 times.

35次。

This is more nominations than anyone else ever in history.

這比歷史上任何一個人的提名都多。

And the number of times he won was roughly the same number of times

而他獲勝的次數也大致相同。

that everyone else in the world has won.

世界上其他所有人都贏了。

Which is zero.

也就是零。

Lewis disliked this a great deal.

劉易斯很不喜歡這個。

It's kind of like a baseball player having more hits than any other player in history

這有點像棒球運動員比歷史上任何其他球員擁有更多的命中率。

and no home runs.

而沒有全壘打。

He may have been the most influential chemist of all time.

他可能是有史以來最有影響力的化學家。

He coined the term photon, he revolutionized how we think about acids and bases

他創造了光子一詞，他徹底改變了我們對酸和鹼的看法

and he produced the first molecule of heavy water.

並且他產生了第一個重水分子。

He was the first person to conceptualize the covalent bond that we're talking about right

他是第一個概念化我們正在談論的共價鍵的人。

now.

現在。

Gilbert Lewis died alone in his laboratory while working on cyanide compounds

吉爾伯特-劉易斯在研究氰化物時，獨自一人死在實驗室裡。

after having had lunch with a younger, more charismatic colleague

和一個更年輕、更有魅力的同事吃過午飯後

who had won the Nobel Prize and who had worked on the Manhattan project.

曾獲得諾貝爾獎，曾參與曼哈頓項目的。

Many suspect that he killed himself with the cyanide compounds he was working on

很多人懷疑他是用他正在研究的氰化物自殺的。

but the medical examiner said heart attack, without really looking into it.

但法醫卻說是心臟病，沒有真正查清楚。

I told you all of that because

我告訴你這些是因為

the little Lewis dot structure that we use to represent how atoms bond to each other

劉易斯小點結構

is something that was created by a troubled mad genius.

是一個麻煩的瘋狂天才所創造的東西。

It's not some abstract scientific thing that's always existed.

它'不是什麼抽象的科學的東西，'一直存在。

It's a tool that was thought up by a guy

這是一個人想出來的工具。

and it was so useful that we've been using it ever since.

而且它是如此有用，我們'一直在使用它，因為。

In biology most compounds can be displayed in Lewis dot structure form

在生物學中，大多數化合物都能以劉易斯點結構形式顯示出來

and here's how that works:

和這裡'的如何工作。

These structures basically show how atoms bond together to make up molecules.

這些結構基本上顯示了原子是如何結合在一起組成分子的。

And one of the rules of thumb when you're making these diagrams

當你做這些圖的時候，有一個經驗法則就是

is that the elements that we're working with here react with one another in such a way

是，我們在這裡工作的元素彼此之間的反應，以這樣的方式。

that each atom ends up with 8 electrons in it's outermost shell.

每個原子最後都有8個電子在它'的最外層。

That is called the Octet Rule.

這就是所謂的八分法則。

Because atoms want to complete their octets of electrons to be happy and satisfied.

因為原子要完成自己的八次電子，才會快樂和滿足。

Oxygen has 6 electrons in it's octet and needs 2 which is why we get H2O

氧氣有6個電子，需要2個，這就是為什麼我們會得到H2O。

It can also bond with carbon

它也可以與碳結合

which needs 4.

其中需要4。

So you get 2 double bonds to 2 different oxygen atoms and you end up with CO2.

所以你得到2個雙鍵到2個不同的氧原子上，最後就得到了二氧化碳。

That pesky global warming gas and also the stuff that makes all life on Earth possible.

那討厭的全球變暖氣體，也是讓地球上所有生命得以存在的東西。

Nitrogen has 5 electrons in its outer shell. Here's how we count them:

氮的外殼有5個電子。這裡'是我們如何計算它們。

There are 4 placeholders. Each of them wants 2 atoms.

有4個佔位符。他們每個人都想要2個原子。

And like people getting on a bus they prefer to start out not sitting next to each other.

而像人們上公車一樣，他們更願意一開始就不挨著坐。

I'm not kidding about this, they really don't double up until they have to.

我'不是在開玩笑，他們真的是不到萬不得已不會加倍。

So for maximum happiness, nitrogen bonds with 3 hydrogens, forming ammonia.

所以要想獲得最大的幸福感，氮與3個氫結合，形成氨。

Or with 2 hydrogens sticking off another group of atoms, which we call an amino group.

或者用2個氫從另一組原子上粘下來，我們稱之為氨基。

And if that amino group is bonded to a carbon that is bonded to a carboxylic acid group

如果該氨基基團與與羧酸基團結合的碳結合在一起

then you have

那麼你就

an amino acid!

氨基酸！

You've heard of those, right?

你聽說過這些，對嗎？

Sometimes electrons are shared equally within a covalent bond like with O2.

有時電子在共價鍵內是平等共享的，比如O2。

That's called a non-polar covalent bond. But often one of the participants is more greedy.

這就叫非極性共價鍵。但往往其中一個參與者比較貪心。

In water for example, the oxygen molecule sucks the electrons in

例如，在水裡，氧分子會把電子吸進去。

and they spend more time with the oxygen than with the hydrogens.

他們花更多的時間與氧比與氫。

This creates a slight positive charge around the hydrogens

這將在氫的周圍產生輕微的正電荷。

and a slight negative charge around the oxygen.

和氧氣周圍的輕微負電荷。

When something has a charge we say that it's polar. It has a positive and negative pole.

當一個東西有電荷時，我們說它是極性的。它有一個正極和負極。

And so it's a polar covalent bond.

所以它'是一個極性的共價鍵。

Now let's talk for a moment about a completely different type of bond, which is an ionic

現在讓我們來談一談一種完全不同的鍵，即離子型的鍵

bond.

債券。

And that's when, instead of sharing electrons

這時，不是共享電子，而是分享電子。

atoms just completely wholeheartedly donate or accept an electron from another atom

原子全心全意地捐贈或接受另一個原子的電子

and then live happily as a charged atom.

然後作為一個帶電的原子快樂地生活。

And there is actually no such thing as a charged atom.

而實際上並不存在帶電原子這種東西。

If an atom has a charge, it's an ion.

如果一個原子有電荷，它就是一個離子。

Atoms in general prefer to be neutral, but compared with having a full octet, it's not

原子一般都喜歡中性，但與有一個完整的八位數相比，它'不

that big of a deal.

這麼大的交易。

Just like we often choose between being emotionally balanced and sexually satisfied

就像我們經常會在情感平衡和性滿足之間選擇

atoms will sometimes make sacrifices for that octet.

原子有時會為了這個八位數做出犧牲。

The most common ionic compound in our daily lives is salt.

我們日常生活中最常見的離子化合物是鹽。

Sodium chloride. NaCl.

氯化鈉。氯化鈉。

The stuff, despite it's deliciousness, as I mentioned previously

這東西，儘管它'的美味，正如我之前提到的

is made up of two really nasty chemicals. Sodium and chlorine.

是由兩種非常討厭的化學物質組成的。鈉和氯。

Chlorine is what we call a halogen, which is an element that only needs one electron

氯就是我們所說的鹵素，它是一種只需要一個電子的元素。

to fulfill it's octet.

來履行它'的八字訣。

And sodium is an alkaline metal which means that it only has one electron in it's octet.

而鈉是一種鹼性金屬，這意味著它的八元組中只有一個電子。

So chlorine and sodium are so close to being satisfied

所以氯和鈉就差一點就滿足了。

that they will happily destroy anything in their path in order to fulfill their octet.

他們為了實現他們的八字方針，會很樂意地摧毀任何擋在他們面前的東西。

And thus, there's actually no better outcome than just to get

是以，其實沒有什麼更好的結果，只是為了得到'。

chlorine and sodium together and have them lovin' on each other.

氯和鈉在一起，讓他們互相愛護&#39；。

They immediately transfer their electrons.

它們立即轉移電子。

So that sodium doesn't have it's one extra, and chlorine fills it's octet.

這樣，鈉就沒有它'多了一個，而氯就填滿了它'的八位數。

They become Na+ and Cl- and are so charged that they stick together

它們變成Na+和Cl-，並帶電，以至於它們粘在一起。

and we call that stickiness an ionic bond.

我們把這種粘性稱為離子鍵。

And just like if you have two really crazy friends

就像如果你有兩個非常瘋狂的朋友一樣。

it might be good to get them together so that they'll stop bothering you.

也許是好的，讓他們在一起，這樣他們'就不會再打擾你了。

Same thing works with sodium and chlorine.

鈉和氯也是一樣的道理。

You get those two together, and they'll bother no one.

你把這兩個人放在一起，他們'就不會打擾任何人。

And suddenly, they don't want to destroy, they just want to be delicious.

突然間，他們不想破壞，只想成為美味。

Chemical changes like this are a big deal.

這樣的化學變化是個大問題。

Remember, chlorine and sodium, just a second ago, were definitely killing you, and now

記住，氯和鈉，就在一秒鐘前，絕對是要你的命，而現在

they're tasty.

他們'好吃。

Now we're coming to the last bond that we're going to discuss

現在我們要討論的是最後一個債券的問題了

in our intro to chemistry here and that's the hydrogen bond.

在我們的化學介紹這裡，那'是氫鍵。

Imagine that you remember water, I hope that you didn't forget water.

想象一下，你還記得水，我希望你沒有'忘記水。

Since water is stuck together in a polar covalent bond

由於水是以極性共價鍵粘在一起的

the hydrogen bit is positively charge and the oxygen bit is negatively charged.

氫位帶正電，氧位帶負電。

So when water molecules are moving around

所以當水分子在周圍移動時

we generally think of them as a perfect fluid but they actually stick together a little

我們通常認為它們是完美的液體，但實際上它們是有點粘在一起的。

bit.

位。

Hydrogen side to oxygen side.

氫側對氧側。

You can actually see this with your eyes if you fill up a glass of water too full

如果你把一杯水灌得太滿，其實你可以用眼睛看出來的

it will bubble at the top. The water will stick together at the top.

它的頂部會有氣泡。水會在頂部粘在一起。

That's the polar covalent bonds sticking the water molecules to each other

那是極性共價鍵，將水分子粘在一起

so that they don't flow right over the top of the glass.

以便它們不會直接流過玻璃的頂部。

These relatively weak hydrogen bonds happen in all sorts of chemical compounds