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Hi, I'm Jessica
嗨，我是Jessica
and I'm gonna be talking about a chemical demonstration today that
今天我要讲的化学演示
I like to call bringin' home the bacon
叫作"养家糊口的培根"
Now before we get cookin', let's take a look at the chemist's best friend
在开始烹饪之前，我们先来看看化学家的老朋友
This is the periodic table
元素周期表
It was created in 1869 by the Russian chemist Dmitry Mendeleev
它是在1869年由俄国化学家德米特里·门捷列夫制作
back when only 65 elements were known
当时他制作的表中只有65个元素
Different elements on the periodic table
周期表中的不同元素
require different numbers of electrons to be "happy"
需要不同数目的电子才能"开心"
Electrons live in the shell surrounding atoms
电子位于原子核周围的电子层中
and when an atom's outermost shell is filled to capacity
当原子最外层填满电子时
the atom is "happy"
原子就会"开心"
Now hydrogen over here
这里的氢原子
has one electron in its outer shell
在最外层有一个电子
and needs just one more to fill it
它还需要一个才能填满
Carbon has four electrons in its outer shell
碳最外层有四个电子
and needs four more, a total of eight electrons to fill it
还需要四个才能填满，总共要八个电子
Now on the left and middle of the table, we have the medals
周期表的左侧和中间是金属元素
To get to eight electrons in their outer shell
要在最外层得到八个电子
the medals lose electrons
金属需要失去电子
And on the right side of the table, we have nonmetals
而在周期表右侧的则是非金属元素
To get eight electrons, these elements gain electrons
要得到八个电子，非金属元素需要获得电子
And hydrogen is the only nonmetal that's on the left hand side of the periodic table
氢是唯一位于周期表左侧的的非金属元素
Now one way atoms get to eight electrons in their outer shell
原子在最外层得到八个电子
is through chemical bonds
需要通过化学键
A bond is the sharing of two electrons between two atoms
化学键是两个原子之间两个电子的共用
So carbon likes to have four bonds
碳喜欢有四个键
and hydrogen likes to have one
而氢喜欢有一个键
Knowing about where the electrons are and how they participate in bonding
了解电子在哪，以及电子如何参与到成键中
is central to many important things in the real world
对于理解现实世界中的各种现象非常重要
For example, unsaturated fats have a double bond
例如不饱和脂肪具有一条双键
lots of electron
很多电子
and that gives them special reactivity
这让其具有特殊的反应活性
which can lead to the spoiling of food when the bonds react with oxygen
当双键同氧气反应时，食物就会变质
