Welcome to the Dance of Chemistry arc. If you're following from the Elemental Flow arc, you have a perspective that many high-schoolers don't. To put you at ease, there’s a lot less quantum mechanics in this part. In fact, many chemistry students begin learning from here. It's a solid place to begin in any of the sciences.
Remember the guy at the beginning of the Elemental Flow arc that I was telling you about? That dude that shows off by telling everyone how many invitations he gets at parties? We'll address him in the next section. As for now, allow me to introduce you to the atomic dance.
Society of Atoms
If you’re like those that (understandably) feel the need to be within every social circle, then you’re likely a part of 90% of the atoms. But if you’re the type to (rightfully) believe that being invited to parties isn’t significant in the grand schema, then you’re a noble gas.
Although all atoms are different, they all seek one thing: to be like the noble gases. They are completely content with their existence with no need for social validation. The standards that a noble gas holds puts it in a league of its own. They are the ones that accept the invitations and throw the parties.
But these invitations are not like conventional ones, where there is one invitation for one party. Unless you are born in the noble gas class, you have to collect a certain number of invitations to be admitted into their ranks. Furthermore, those invitations can only be gained by pooling together yours with those of a compatible person. The problem is that it’s not possible for everyone who is compatible to meet at any time. That forces some atoms have to get creative. Sometimes, given everything you are, you can only thrive in a certain environment; you can only dance with those looking for someone like you.
There is order to the madness of the social dance of atoms. Amazingly, they partake in this dance for their own satisfaction. To understand what might seem like madness to us, we had to discuss orbitals as they outline which atoms can dance and how. This is the perspective which starting chemistry students lack. Starting from here is fine, but, consequentially, there is no easy way for one to understand the atom's motivations (this is your obligatory warning to go back and read through the Elemental Flow arc).
Let’s take a look at hydrogen. This atom only has one electron in normal cases. The poor atom hasn’t gotten many invitations and understands that receiving one will put it at ease.
But why only one?
Hydrogen exists in the 1s orbital. The 1s orbital is allowed two electrons, each with opposite spins. All elements desire to fill their outermost electron shell, or their valence shell. That means, in order for hydrogen to be as stable as possible, it needs to have another electron.
Care to Dance?
How does hydrogen determine who to exchange electron invitations with? You can imagine that, if you, as hydrogen, wanted to be like one of the amazing noble gases, you would pick the one nearest to you in personality to emulate. It so happens that the one nearest to hydrogen is helium.
Of course, that decision is in the name of energy. Noble gases have full valence shells, meaning they are more stable than atoms that do not. The reasons for this are found in the properties of each atom, explained by the quantum numbers (EF 4-5) that represent them. For example, an electron without its opposite spin will be of higher energy than an electron with its opposite spin. Also, the nucleus is positively-charged, and attracts electrons. With enough electrons, the nucleus’ positivity is blocked by the negative charge of the electrons, and so, it cannot attract anymore giving the atom a lower binding energy. That effect is called electron shielding, a term you’ll undoubtedly hear again soon.
Helium, with its two electrons for its two protons, and a full outer shell, is, indeed, something hydrogen should want to emulate. But I digress, the original query tries to get to the root of what hydrogen binds to.
Here, I would like to introduce the diatomic nature of atoms. A diatomic molecule is that which is composed of two atoms. It so happens that hydrogen exists in nature as a homonuclear diatomic molecule, meaning that it's two atoms are the same.
This certainly fixes hydrogen’s problem doesn’t it? They each have one electron, represented by a red dot in the above image, and they are willing to share by forming a covalent bond. By combining their electrons they both satisfy each other. The best part is that they both have the necessary amount of invitations to join the noble gases at their next party.
It’s Not Always So Pleasant
Hydrogen is often used as an example to explain facets about atoms because it is the simplest atom we can use. But there are many more atoms on the periodic table. And, unfortunately, they don’t all play nice. In many cases, the introduction of another atom will disturb the whole system…like that guy who flaunts all his electrons and wants more. Let’s give him a name now: oxygen. And, just because oxygen likes to feel good about himself, we’ll make sure he gets all the attention he deserves in the next part.
As always, thank you for joining me on this new arc. Please feel free to ask any questions you have and join our new mailing list for notice on new articles.