What gives atoms the properties of a chemichal?

[silenzer]

Firstly be easy on me, I'm 17 and still in high school and English is not my first language so go easy on the heavy vocabulary.

I was wondering the other day, what is it that gives atoms its properties? If air would be densed to as thick as water, would it have the same properties? I don't think so, but why not?

[SpectraCat]

First a little terminology:

Atoms are classified by element. The organization of electrons in the atoms gives each element its properties.

Water is a molecular compound .. it is made up of hydrogen atoms and oxygen atoms bound together by covalent bonds.

Air is a mixture of gases .. it is mostly molecular nitrogen (two nitrogen atoms bound together) and molecular oxygen (two oxygen atoms bound together), with some other minor components.

So, you are correct that air compressed to the same density as water will have different properties that liquid water. The reason for this is because the different substances are composed of different combinations of atoms at the molecular level. I can't go much beyond this without getting significantly more technical.

[Borek]

what is it that gives atoms its properties?

As SpectraCat wrote, it is arrangement of electrons that defines properties. This arrangement is in turn function of the nucleus charge, that is different for each element (but identical for all atoms of the same element).