[smghz]

I LOVE chemistry, and when I say that, I mean it. I like learning about the physical composition of literally everything.

However, I don't get much of it. Yes, I know the basics, like protons, electrons, and neutrons, the periodic table (even if its structure makes NO sense to me). Yet I don't understand much of it. I don't understand why H2O is written as H2O. I don't get why some atoms are polar while others aren't. I don't comprehend the fact that atoms can combine (and how, and why don't they combine when I touch the keys on my keyboard?).

Please don't understand this as a rant. I had chemistry in high school just last year and I didn't get it because it was not taught the way it is taught in other schools, and that is okay. But I am a person who has a potential in studying chemistry in college, and the only thing barring me is the understanding of it. I just hate it when Hank Green and Paul Andersen talk chemistry thinking that students would automatically understand things. I don't. I am trying really hard to wrap my head around chemistry, but it does not only look incomprehensible; it seems so unbelievable.

[cseil]

I LOVE chemistry, and when I say that, I mean it. I like learning about the physical composition of literally everything.

However, I don't get much of it. Yes, I know the basics, like protons, electrons, and neutrons, the periodic table (even if its structure makes NO sense to me). Yet I don't understand much of it. I don't understand why H2O is written as H2O. I don't get why some atoms are polar while others aren't. I don't comprehend the fact that atoms can combine (and how, and why don't they combine when I touch the keys on my keyboard?).

Please don't understand this as a rant. I had chemistry in high school just last year and I didn't get it because it was not taught the way it is taught in other schools, and that is okay. But I am a person who has a potential in studying chemistry in college, and the only thing barring me is the understanding of it. I just hate it when Hank Green and Paul Andersen talk chemistry thinking that students would automatically understand things. I don't. I am trying really hard to wrap my head around chemistry, but it does not only look incomprehensible; it seems so unbelievable.

My relationship with chemistry started in high school, reading books about chemistry like "Napoleon's buttons: how 17 molecules changed history" and things like that.
They are written in a vey simple way, you can understand very easily what they say because it's not about chemistry, but it's about where's chemistry.

After a few years (chemistry in high school is very basic) I went to the university and I started studying industrial chemistry.
In college you start studying serious stuff: not where's chemistry but what it is, how it works, how to understand the world with it.

Then you go to the lab. Going to the lab is the most amazing experience if you love chemistry. At first it's all about colours and magnificient reactions, then you begin to understand also what you cannot see, and it's even better

I'm in my last year now (undergraduate) but it's only the beginning.

Now, I don't understand how do you say "I love chemistry, but I cannot understand it".
Explain your problems. How did you study it? Have you studied from a book?

[smghz]

Thank you for your response (or sympathy). I really appreciate it. I love chemistry as a subject, because it is cool and awesome. Isn't that how everyone chooses his/her major does anyway by loving a subject then learning deeper into it?

My problem with chemistry is that it is too complicated to understand. These are just excerpts from a chem book:

1. Electrons in the lowest available energy level are said to be in the ground state. When an atom absorbs energy, its electrons move to a higher energy level.

So what does this mean for God's sake? What do electrons have anything to do with energy levels?

2. Ionic bonds form when electrons are transferred. Covalent bonds form when atoms share electrons.

Okay, what is the difference here between the transfer and the sharing? Aren't they the same thing which is giving?

3. The H2O structure:

Okay, so I don't understand what happens to the electrons here. Why is it not just HO, or HO2, or some other nonsense thing?

4. There are three types of intermolecular attractions: polar-polar, hydrogen, and nonpolar.

What is hydrogen doing here, then? Why can't it be just classified as polar-polar or nonpolar (what are these terms anyway??).

Please don't feel compelled to answer these questions. I just wanted to provide a background of my thinking of chemistry, and how I can think of it differently so I can start learning it correctly and at least without any dam-high obstacles (I like challenges, but not impossible ones).

[Corribus]

1. Electrons in the lowest available energy level are said to be in the ground state. When an atom absorbs energy, its electrons move to a higher energy level.

So what does this mean for God's sake? What do electrons have anything to do with energy levels?

Unlike, say, tennis balls, which are allowed to be anywhere, electrons and other small particles are only allowed to be in certain places. This is because their energies are quantized, meaning they can only have certain values. (In principle, the energies of tennis balls may be quantized, too, but the allowed levels are so close together for massive objects that the distribution might as well be continuous.) We call these "energy levels". To travel between energy levels, electrons have to absorb exactly the same energy as the difference between the two levels. Imagine you are at the bottom of a hill, and I tell you to walk up it.  Since you are not a quantum particle, you can walk any distance up it you want, expending any amount of energy you want. If you were a quantum human, there would only be certainly places on the hill you'd be allowed to come to a rest. These would be your allowed energy levels. If I gave you an amount of candy bars that had exactly enough energy to get to one of these other allowed levels, you could reach one of those levels. If I gave you slightly more or slightly less, you wouldn't be able to do anything with those candy bars, and you couldn't go anywhere.  The lowest allowed levels (the bottom of the hill) is the "ground state". Anything else is an "excited state".

2. Ionic bonds form when electrons are transferred. Covalent bonds form when atoms share electrons.

Okay, what is the difference here between the transfer and the sharing? Aren't they the same thing which is giving?

Some atoms like electrons more than others. If there is a big difference between how much two atoms like electrons, one electron essentially steals all the electrons from the other. The electron that steals the electrons is negatively charged. The electron from which electrons are stolen is positively charged. Because of these opposite charges, they stick together. This is an ionic bond. If the atoms like the electrons the same amount, the electrons are shared between the two. You can think of the nuclei as positively charged, and the electrons are negatively charged. Since the atoms are sharing the electrons, they are between the two nuclei. This is a covalent bond. The attraction of positive and negative charges holds atoms together in both cases. It's a matter of where electrons are located. In truth, ionic and covalent bonds are sort of extreme cases - most systems have some degree of sharing. 

An analogy: two children have one toy each, and they are put in a room to play. If one of the children is a bully, he takes the other child's toy, so now he has two. But the child with is still attracted to the one with both toys, because all children like toys. So he still hangs around the bully, hoping to at least experience the joy of being around toys. (This is an ionic bond.) On the other hand, if neither child is capable of stealing the toy from the other, they decide to share the toys and play together. Obviously, they stick together in this case as well. (This is a covalent bond.)

3. The H2O structure: (edited out)
Okay, so I don't understand what happens to the electrons here. Why is it not just HO, or HO2, or some other nonsense thing?

More complicated. In a simple view that suitable for your level, most atoms like to have what's called a full outer shell of electrons. Going back to the toy analogy, imagine there are a set of toys that belong together. You aren't really going to be happy unless you have the full set, and you will do what it takes to steal enough toys to make the full set. But you won't steal more than that. Likewise, if you have one toy that a friend needs to complete a set, the two of you can share your toys so each of you gets to play with a full set. For reasons related to where electrons are allowed to be, the typical number of a full set is eight (except for hydrogen, for which the number is two). This is called the "octet rule".

Oxygen atom comes with six electrons - because this is the number of protons in the nucleus. Remember, all charges like to balance. Hydrogen atom has one electron for the same reason. Therefore oxygen wants two electrons to make a full set of eight, and hydrogen wants one to make a full set of two. It should be easy to see therefore why oxygen and hydrogen like to combine in a 1 to 2 ratio. Everyone is then working with a full set.

This basic principle can be used to understand a lot of simple chemistry. For example, ammonia has the formula NH₃. Why NH₃? Well, nitrogen atom has five (valence!) electrons. Hydrogen again has one. Nitrogen needs three electrons for a full set. Now you see why NH₃! Now you see why methane has formula CH₄?

Obviously, it becomes more complex and there are many more rules, particularly to understand why reactions occur, but start with simple cases and then you can build from there.

4. There are three types of intermolecular attractions: polar-polar, hydrogen, and nonpolar.

What is hydrogen doing here, then? Why can't it be just classified as polar-polar or nonpolar (what are these terms anyway??).

Realize: All interactions in chemistry are electrostatic - they relate to the interactions between positive and negative charges. We create categories to help us understand why some interactions are stronger than others, but these categories are often somewhat artificial. Hydrogen bonds are really just a special kind of dipole (polar-polar) interaction that is unusually strong because the hydrogen is very positively charged when in the neighborhood of a big bully like oxygen, which is very negative. In water, oxygen likes to hog all the electrons from hydrogen. It is covalent - electrons are shared - but the sharing is uneven. Even though they share, electrons spend a majority of their time near oxygen. This means that oxygen has a lot of negative charge and hydrogen has a lot of positive charge (remember above where I said that covalent and ionic are extreme cases, and in reality it's somewhere in between?). Since the oxygen of one water molecule is negatively charged and the hydrogens of nearby water molecules are positively charged, they tend to attract each other. This is not fundamentally different from dipole interactions between other molecules - it's just a matter of scale.

There's really no such thing as "nonpolar interactions". What are often called van der waals interactions are still interactions between positive and negative charge. Some molecules don't have any permanent differences in the way charges are distributed. Everything kind of evens out, unlike in water. We call these molecules "nonpolar" because they don't have permanent dipoles. However be aware that electrons are always in motion. So even though everything evens out in a nonpolar molecule, at any point of time there might be a few more electrons on one side of the molecule than others. These are "temporary dipoles". So if two nearby nonpolar molecules each have temporary dipoles, these temporary dipoles can stick together temporarily. You would be correct to expect these interactions to be weaker than most permanent dipole interactions, and even weaker still than really strong hydrogen bonds.

Intermolecular interactions are very important in chemistry because they determine a lot of the physical properties of chemicals. Water has very strong hydrogen bonds, as mentioned, and therefore it takes a lot of energy to break them apart. Hence the high boiling point of water. Compare that to methane, whose molecules are only held together by weak "nonpolar" van der waals interaction, and has a boiling point many many many degrees lower.

Feel free to ask other questions here. That's what we're here for. The only way to truly learn chemistry is to keep asking questions. You will eventually begin to understand, do not fear. It all starts with interest, and you seem to have that. So you're on the right path.