[smghz]

I'm interested in knowing how are elements like oxygen, nitrogen, and hydrogen and their atoms are seen/observed, how they're isolated, etc.

[smghz]

I mean, is it the reason that gold is yellowish, that paper turns into ashes when burned, that something is hot while another is cold? I want to know what the atom influences.

[smghz]

If you had a lined sheet of paper, and you've ripped it right in the middle, what exactly (if not, then theoretically) occurs to the atoms there?

[smghz]

Our hands touch many things in the world, like tables, papers, keyboards, phone screens, and even the air. Why aren't there any reactions going on if the atoms do touch each other???

[AdiDex]

hey buddy can you explain a little more about your question so that i can help you. I don't understand "The Reason " given by you .

By the  way color of a substances is mainly due to its electronic configuration (How electrons are arranged around the atom or molecules ), also on the no. of proton inside the nucleus .

It is very fascinating phenomena. what happens at the microscopic level , how light interact with electron , it is mainly a field of a Physicist (saying more precisely , Particle physicist) . 

[AdiDex]

First Misconception -> we can't touch any atom and electron .

To understand this You should watch this video ,Dr. Derek Muller from Veritasium explains it in a very good manner .

https://www.youtube.com/watch?v=bKldI-XGHIw

Second Misconception -> only touching anything do not make anything react.

Every reaction occur to make its system more stable than before . Think like this if table is already stable then why it will react by itself .
OK but you can proceed a reaction by forcefully .
another thing is that every reaction need some energy to get start .pushing gently do not provide that much energy so that you can observe the effect of your pushing .
Chemical reaction is not about to push or pull anything it is all about how two atoms or molecules are bonded before the reaction and after the reaction.

To understand this you can watch this video -

https://www.youtube.com/watch?v=8m6RtOpqvtU

any other query just post it.

[AdiDex]

You just broke some bonds between molecules ( breaking atom's bond is not so feasible ) .

may be some bonds between atoms will break but the fact is that a individual atom is very reactive (Except atoms of noble gases) . SO as you rip them apart they will react with something which is around them.

So logically you are breaking some bonds.

[AdiDex]

that's a very good question. are you from USA ??
if yes i have a very good video for you, in which you will get your all answer about elements specially about air.

http://video.pbs.org/video/2365543486/

watch this , the problem is that you can access this video if you belongs to USA.

In case , you are not from USA .you have a another option -
Download hola extension to your Mozila or chrome -:
for chrome i have link-:
https://chrome.google.com/webstore/detail/unlimited-free-vpn-hola/gkojfkhlekighikafcpjkiklfbnlmeio?hl=en

Enable it by going into your chromes setting---> Extensions----> Check the enable box of hola extension.

Go to given website that is
http://video.pbs.org/video/2365543486/
there will be hola's icon in the right of address bar , click on it. Choose united states.
ta da... Your video will be started.
Name of video is "Mystery of matter : out of thin air"
you get all of your answers. How elements extracted ? how air is separated into its contituents etc etc. .

Please do fast because these videos are only available till 19th of September .

You can download them By Internet Download Manager (IDM) to watch them later.

[AdiDex]

A suggestion for you .
Please don't skip anything , start from basic . Be a good listener and question everything .  You are very curious which is the main aspect of a science student . That's a nice start .

[Arkcon]

I hope you don't mind, smghz:, that I merged your similar questions into one post.  Its good to have everything together, so you can build from what you've already seen.  And apologies to AdiDex: as well, for the effect merging had on his posts.

[Enthalpy]

Every reaction occurs to make its system more stable than before.

No. It's a matter of entropy, not of released heat.

[Enthalpy]

...the reason that gold is yellowish...

According to the "electron gas" model, metals have some mobile electrons, whose density defines the minimum energy of photons that are absorbed by a plasma cutoff frequency. The model woks not too badly for metal colour.

At copper, the minimum energy is smaller, so red light is reflected but other colours are absorbed. At gold, the threshold is higher, more colours are reflected, and it appears yellow. At silver, most colours are reflected, and it appears white.

[Enthalpy]

If you had a lined sheet of paper, and you've ripped it right in the middle, what exactly (if not, then theoretically) occurs to the atoms there?

Atoms in paper organize as molecules (for instance cellulose) which organize as fibers. Fibers hold weakly together by small interactions between the molecules at the fibers' surface (and supposedly more means) which you break to separate the fibers and rip the paper.

[AdiDex]

Enthalpy , I was just trying to tell him/her from very basic . (So i didn't mentioned entropy as he/she is a beginner , don't bombard the concepts on his face)

You are also partially correct from my point of view.

Usually what we talk about  is Gibbs free Energy . Gibbs free energy is the useful energy or work , so basically you are decreasing its useful energy .

[smghz]

...would it still look the same? (e.g. gold).