First post, hello, I have a lot of questions.

[exchemist]

19 minutes ago, Jack777 said:

Sorry. I meant the people back back then who used the terms hooks.

How did they determine if something was bonded?

This set of formulas above is quite complicated to me. It's difficult to visualize. I'm sure in time I'll get there.

Thanks again.

By observing the proportions in which substances reacted. Once you have the atomic weights, if you carefully weigh the reactants and the products, you can deduce that one carbon atom reacts with 4 hydrogen atoms, or else to produce substances with the ratio nC atoms: 2n+2 H atoms. In other words, CH4, C2H6, C3H8………..etc. These are all hydrocarbons. Probably easiest to do it by burning some of a hydrocarbon and measuring the amount of water and carbon dioxide produced and looking at their ratios.

And then it dawns on you that C is joining to 4 other atoms, either 4 Hydrogen or else to one or more C atoms and H for the remainder, but H is only joining to one other atom. The lines between that atoms signify that C can join to 4 atoms but H can only join to 1 . This led to the idea that the number of “bonds” an atom can form is characteristic of the element.
 

And that is a very powerful principle in chemistry.

Edited 21 hours ago by exchemist

[Jack777]

2 minutes ago, exchemist said:

By observing the proportions in which substances reacted. Once you have the atomic weights, if you carefully weigh the reactants and the products, you can deduce that one carbon atom reacts with 4 hydrogen atoms, or else to produce substances with the ratio nC atoms: 2n+2 H atoms. In other words, CH4, C2H6, C3H8………..etc. These are all hydrocarbons. Probably easiest to do it by burning some of a hydrocarbon and measuring the amount of water and carbon dioxide produced and looking at their ratios.

And then it dawns on you that C is joining to 4 other atoms, either 4 Hydrogen or else to one or more C atoms and H for the remainder, but H is only joining to one other atom. The lines between that atoms signify that C can join to 4 atoms but H can only join to 1 . This led to the idea that the number of “bonds” an atom can form is characteristic of the element.
 

And that is a very powerful principle in chemistry.

A principle I don't yet grasp because how do they measure atoms? I guess I have to learn about atomic weights.

[exchemist]

32 minutes ago, Jack777 said:

A principle I don't yet grasp because how do they measure atoms? I guess I have to learn about atomic weights.

I made a post about, that a while back on this thread. 
 

But the idea of bonds, and thus the meaning of the diagrams @studiot showed you, should not be too hard for you to understand, I hope.

Water is H-O-H. Carbon dioxide is O=C=O (double lines in the latter case denoting what are called “double” bonds. Note that in this case carbon still forms 4 bonds, even though here it is joined to only 2 other atoms.) So you can see O, oxygen, forms 2 bonds, C, carbon 4 and H, hydrogen 1. 

Edited 20 hours ago by exchemist

[Jack777]

2 minutes ago, exchemist said:

But the idea of bonds, and thus the meaning of the diagrams @studiot showed you, should not be too hard for you to understand, I hope.

Sorry, it is hard for me to understand. I'm going to read the books I bought and hopefully I will be able to grasp it. 

[studiot]

2 hours ago, Jack777 said:

Sorry, it is hard for me to understand. I'm going to read the books I bought and hopefully I will be able to grasp it. 

This table might help and it will be useful in time period 4 the last in our history.

I am showing what happens with one gas that doe not combine with itself (helium) and three gases where two atoms of each of the gases combine with each other to form one molecule conprising two atoms. That is a diatomic molecule.
Helium is a monatomic molecule.

The valencies are 0, 1, 2 3   - I don't know of any diatomic gas molecules formed from atoms with higher valencies than 3.

So the pattern is that you require two atoms , alike or different to form one bond.  - my examples are both alike for ease.

It is also possible to more than two atoms to combine to form molecule but that will always involve additional bonds.

Note the number of hooks is the same as the valency.

If you hook two hooks together you get one bond.

If you have zero valency there are no hooks which is why two helium atoms will not join together so a helium molecule has only one atom in it and is called monatomic.

side note

Careful here, you may come across the terms monovalent, divalent and trivalent.

There is no term for nil valent.

end side note

 

Molecules occur mostly in gases. Solids can be quite different.

Do you understand anything about solids, liquids and gases. Have you heard of the kinetic theory ?

 

[Jack777]

1 hour ago, studiot said:

This table

I apologize in advance, this too is still over my head. Honestly, way over my head. I'm still trying to grasp how they knew something was a molecule.

I just started listening to a podcast today called The History of Chemistry by Steve Cohen. So far this is easy for me to follow and understand. I like what he said how it was described, "A chemical process is invisible with no obvious explanation." 

If you need to quit I'll understand as this is a slow process for me but I will eventually get it.

Thanks.