And I look up and see that 55 the electronegativity of carbon is 2.55 2 we already know, is 2.20.
我查了一下电负性,碳是2。,2。
if we think about electronegativity as a periodic trend we can just draw our nice periodic table here, and let's separate it into quadrants.
如果我们来思考一下电负性的周期性规律,我们可以把我们漂亮的周期表画在这,然后把它分成四个象限。
He introduced the concept of electronegativity which was a measure, therefore, it is quantitative, of the atom's ability to attract electrons within a covalent bond and developed a scale of electronegativity.
他引入了电负性这一概念,一个反映着原子在成共价键时吸引电子的能力的数据标度,因此这是数量上的,在共价电子中,电子原子能吸引电子,并发展为一定规模的电负性。
All right, so it's very common to talk about electronegativity of different atoms, and you can look up tables of these.
好,这是很常见的,对于不同原子电负性的讨论,大家可以查阅这方面的表格。
We'll then take a turn to talking about the periodic table, we'll look at a bunch of periodic trends, including ionization energy, electron affinity, electronegativity and atomic radius.
然后我们再开始讲元素周期表,我们会看到很多周期性规律,比如电离能,电子亲和能,电负性以及原子半径。
So we need to go to this second case where we're instead going to think about electronegativity, and we want to think about which atom is the most electronegative.
因此我们需要转到这个第二种情况,来考虑一下电负性,我们需要想想哪个原子的电负性是最高的。
You see the difference in electronegativity, square it, multiply it by one-quarter and raise that to the power e.
你看到了电负性的差异,开方,乘以四分之一,在移到e上去做指数。
And in contrast, in the lower left hand part of the periodic table, these 2 quantities are low, so also what we're going to see is low electronegativity.
相反地,在周期表的左下部分,这两个量的值都很小,因此我们会看到这里的电负性也很低。
We talked about ionization energy, electron affinity, we talked about electronegativity, which is just kind of a combination of the first two, and then ended with atomic radius here.
我们讲了电离能的,电子亲和能的,还讲了电负性的,也就是前两个的组合,最后讲了原子半径的。
So you can think about how these 2 things combined are going to be electronegativity, which is a measure of how much an atom wants to pull electron density away from another atom.
因此你可以想象出,这两样性质合起来就是电负性,也就是一个度量,关于一个原子,有多希望把另一个原子的电子密度拉过来的。
So, in contrast, if it has a low electronegativity, this then is going to be an electron donor.
那么,相反地,如果它的电负性很低,它将会是一个电子的施主。
And since carbon's electronegativity is higher than that of hydrogen, which you would expect from where carbon lies on the Periodic Table. Think about it.
碳的高于氢的,你也可以从碳在,元素周期表上的位置,判断出来,试想一下。
I was so proud of myself getting the lecture notes finished early and handing them in to CopyTech, and then I realized we didn't do electronegativity on Wednesday.
我感到很自豪,对自己能够提前做完讲义,并交给复印中心但是之后我才想起来,我们周三没有讲电负性。
Well, let's see something really crazy with electronegativity.
让我们看一些东西,关于电负性的。
And this looks a lot like the average valence electron energy where the lowest values of electronegativity are in the metallic zone and the highest values of electronegativity are on the nonmetallic zone.
这看起来像是平均电子能,最低的电负性在,金属区最高的电负性在,非电子区。
And, this is the difference in electronegativity between the two elements, all right?
就是在两个元素之间的,电负性的差别?
So if we think about the upper right hand part of the quadrant, well, this is where we're going to have high electron affinity and high ionization energy, so we're also going to see high electronegativity here.
那么让我们来看看右上方的部分,好,在这里我们将会有高的电子亲和能,与高的电离能,因此我们会看到这里的电负性也很高。
Often what you'll see is not a table based on this definition, but something that's called the Pauling definition of electronegativity, but it's exactly the same idea and the same trend as this more numerical way to think about what the meaning of electronegativity is.
通常你看到的表格一般都不是基于这种定义的,而是基于,鲍林定义的电负性,但在意义上是相同的,并且满足同样的周期性规律,当和这种这种更数值化地理解电负性的定义,作对比时。
If you look at the electronegativity difference 73 for sodium iodide, it is 1.73.
如果你看到电负性之差,对碘化钠来说,是1。
I know neon has a higher yet electronegativity, but normally it is inert.
我知道氖有个更高的电子力,但在常态下它是惰性气体。
And so, this is a schematic of the electronegativity scale.
因此,这是电负性大小的示意图。
And the functionality goes as the square of the difference in electronegativity.
这个公式的泛函性与电负性之差,的平方成比例。
So, when we're talking about the idea of electronegativity, essentially what we're talking about is the ability for an atom to attract electron density from another atom.
那么,当我们在讨论电负性这一概念的时候,本质上我们讨论的是一个原子的吸引能力,用来吸引另一个原子的电子密度的。
Cesium versus gold is the same delta electronegativity difference.
铯和金,具有相同的电负性差。
So how do we use this electronegativity?
所以我们应怎样利用这个电子力呢?
And, he defined a term called the electronegativity.
于是他提出了电负性这个理论。
And to measure the intensity of unequal sharing, we take the difference in electronegativity, which I am going to use the Greek symbol chi for.
要度量非平均的程度,我们考虑电负性的差异,我要用希腊语第22个字母chi来表示电负性。
And if we talk about what's going on in areas, or with atoms that have high electronegativity, and we think about whether they're electron donors or electron acceptors, what would you expect for an atom that has high electronegativity?
如果我们要讨论这片区域的情况,或者说讨论这些电负性很高的原子,我们会把它们想象成电子的施主,还是受主?,大家认为哪一种,是电负性很高的原子?
So there is a difference in electronegativity.
所以这他们之间有电负性差。
So, if you can flip your lecture notes over and just write on the blank space, we're going to cover electronegativity first here, and specifically, you can go back and fill this in to your lecture 9 notes, if you want to stay organized, but I just suggest just writing it on lecture 10 notes now and going back.
因此,请大家把讲义翻到背面,就在空白处做一下笔记,我们要先讲一讲电负性,特别提醒一下,大家可以,回到第九课的讲义并把这些记在那里,如果你想保持条理性的话,但是我建议大家先写在第十课的讲义上,回去再记到第九课的讲义上。
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