Formation of different compounds by the same two elements?

Question

Okay, I'm reading about the atomic theory and how it explains the formation of different compunds by the same two elements, right? Well, it explains that "only whole atoms combine in chemical compunds between the same elements. Therefore, different compunds formed by the same two elements must result from combinations of different relative numbers of atoms."

Can you explain this in English for me?

Answer 1

To have a better understanding we have to look the mechanism that makes several atoms of two different elements to come together and form these diverse compounds.

One such mechanism is covalent bounding. Same element can exhibit different valence in bonding to an atom of the same or different element. Every atom in bonding wants to fill their valence shell with a certain number of electrons. If the atoms can't take they share.

The magic number of electrons to fill that common valence shell is 8.

Lets take Oxygen and Hydrogen. Hydrogen atom has one electron and oxygen atom has 6. This is why two hydrogen atoms are being combined with one oxygen atom to form water (The total number of electron involved for this covalent bond is 8)

water is H2O or in terms of a valence bond it is H-O-H

lets take hydrogen peroxide H2O2 or H-O=O-H
The + sign represents that two atoms of oxygen share a covalent bond. Note that in bonding again 8 electrons are involved.

And so on.

Answer 2

Let me give you an example.

Green, Purple, and Orange are Compounds

Blue, Red, and Yellow are atomic elements

Since only whole atoms combine compounds of the same elements, only blue and yellow make green. You cannot use other elemental colors or parts of other element colors except yellow and blue to make green.

Fortunately this is false in reality, but a true and good example

Answer 3

Essentially, you can't have half atoms in compounds. Take carbon dioxide and carbon monoxide. Both are compromised of carbon and oxygen, but one is a 1:1 ratio (monoxide is CO) whereas the other is a 2:1 ratio (dioxide being CO2).