HBr So for example, if I want to look at HBr there's a simple case, right, hydrogen bromine.
如果我想研究,这是个简单的例子,溴化氢。
If we take hydrogen peroxide in the liquid state, it can break down to form water and oxygen.
如果我们有一些液态的过氧化氢,它会分解成水和氧气。
It is a double column, You can see, it starts with hydrogen and goes to mercury in ascending order of atomic mass.
双纵栏,你们看到,从氢开始,然后到水银,按原子质量的升序排列。
So when we talk about orbitals in multi-electron atoms, they're actually lower in energy than the corresponding h atom orbitals.
它们的能量实际上,比对应的氢,原子轨道要低。
In contrast, the dissociation energy of a bond for hydrogen, and molecular hydrogen is everywhere around us, we see 432 kilojoules per mole.
相反,氢分子在我们周围到处都是,一个氢分子的离解能,是432千焦每摩尔。
I mean, you would expect that the group one, absent hydrogen, would be the ones that would have the least.
我想,你们可能认为第一主族,没有氢,而氢应该是最小的。
I'm not going to writegiven threemoles of hydrogen at one bar and three degrees, blah,bla I'm going to write it in a compact notation.
我不会写“给定1巴和多少度下,的三摩尔氢分子之类,我会把它写成一个紧凑的形式。
In 1896, Charles Pickering from Harvard found a series of lines in starlight which he attributed to hydrogen, even though they did not fit Balmer.
在1896年,来自哈佛的查尔斯皮克林发现,一系列的星光,他认为那是氢的作用,虽然它们与巴尔末理论不符。
So what we can actually directly compare is the dissociation energy or the bond strength of nitrogen versus hydrogen.
因此实际上我们可以直接进行比较,对氮分子与氢分子的离解能,或键的强度。
The reason is because we already have a full valence shell for our hydrogen, it doesn't want any more electrons.
原因是因为我们的氢,已经有一个排满的价壳层了,它不再需要多余的电子了。
Hydrogen gas it's in its most stable state, right at room temperature and pressure.
和常压下氢气是氢元素,最稳定的状态,这个小“0“
So let's draw the electron configuration of hydrogen, the molecule, molecular hydrogen.
让我们来画氢原子的,电子构型,分子,氢分子。
There are some exceptions, which we'll get to later, but the only a big exception here is with hydrogen, which has a special stability that's associated with two electrons.
但也有一些例外我们将以后再讲,但这里只有一个较大的例外,氢,它的稳定性比较特殊,只需要两个电子。
So what that means is that's how much energy we would have to put into a hydrogen molecule in order to get it to split apart into its two atoms.
它的意义,就是我们需要向一个氢分子中注入这么大的能量,才能将它分解成两个独立的原子。
So, let's compare this to the energy of the h 2 molecule, and we find that that's negative 3,048 kilojoules per mole.
那么,让我们将它与氢分子的能量比一比,我们发现氢分子的能量是负的,3048,千焦每摩尔。
This is the homonuclear bond energy for hydrogen in pure hydrogen. There we have perfect covalency.
这是氢的同原子的共价能,在纯氢中,我们有完美的共价键。
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。
If we know that this is it the dissociation energy for a hydrogen atom, we can also say the bond strength for hydrogen molecule 424 is 424.
如果我们知道了这是一个氢分子的离解能,那么我们也可以说氢分子的键的强度,就是。
And so we can actually think about how do we calculate what the dissociation energy should be for h 2, so let's go ahead and do this.
因此,我们其实可以想到应该如何计算,氢分子的离解能,那么我们开始做一下吧。
We saw the Schr?dinger equation for atomic hydrogen, but you can write it for more complex systems.
我们看过原子氢的薛定谔方程,但其实我们能把他用在更复杂的体系。
So if we talk about hydrogen, how many valence electrons are we talking about? 1.
如果我们讨论的是氢的话,它应该有多少价电子?一个。
Is it going to be hydrogen or nitrogen? Yup, it's going to be nitrogen.
应该是氢的还是氮的?对,应该是氮的。
And the reason we can see that by looking at this graph is that we see that nitrogen when it's bonded is in an even lower well than we saw for hydrogen.
原因可以通过观察这幅图发现,我们看到氮在成键之后将处于更低的势阱中,对氢而言。
Is a hydrogen bond shorter, or is a nitrogen-nitrogen triple bond going to be shorter?
是氢的键更短,还是氮与氮的三键更短?
Last comments: hydrogen, now here, I'm using a little bit of license here.
最新的说法,氢,我在这儿拓展一下。
So, what this lets us do now is directly compare, for example, the strength of a bond in terms of a hydrogen atom and hydrogen molecule, compared to any kind of molecule that we want to graph on top of it.
因此,这让我们现在可以做到直接进行比较,比如,将一个氢原子,和一个氢分子的键的强度,与任何其它类型的分子进行比较,我们只需要把它的曲线也画在这幅图上。
So, in fact, yes, we did confirm that these covalent bond, at least in the case of hydrogen, we have confirmed by the numbers that we are at a lower energy state when we talk about the bonded atom versus the individual atom.
因此,事实上,是的,我们证实了共价键,至少在氢这种情况下,我们通过数据证实了,成键的原子处于能量更低的状态,当其与单个的原子相对比时。
So, in talking about covalent bonds, we should be able to still apply a more general definition of a chemical bond, which should tell us that the h 2 molecule is going to be lower in energy than if we looked at 2 separate hydrogen atom molecules.
那么,既然提到了共价键,我们应该还可以,给化学键下一个更普遍的定义,那就是告诉我们氢分子能量应该更低,与两个分开的氢的单原子分子相比。
So, if we talk about dissociating h 2, we're going from the h 2 molecule, and breaking this bond right in half, so we now have two individual hydrogen atoms here.
那么,如果我们讨论的是离解氢分子,我们将从氢分子开始,使这个键断裂,一分为二,那么就得到了两个分开的氢原子。
So, even though the lines were wrong, he says, no, that is hydrogen.
所以,即使那光线是错误的,他说,不,它就是氢。
应用推荐