What are the rules for drawing molecular diagrams?

[leroyjenkens]

If I have a molecule of pb₂SO₄ for example, how would I draw that? What are the rules that tell me what attaches to what? When it's only 3 or 4 atoms, it's pretty easy to draw them, but when it's more than that, I have no clue what to do.

 

[Borek]

Never heard about such molecule -- I guess you got valence of lead wrong.

This is sulfate - and as such contains SO₄^2- anion, which is the same in all sulfates.

 

[leroyjenkens]

Never heard about such molecule -- I guess you got valence of lead wrong.

This is sulfate - and as such contains SO₄^2- anion, which is the same in all sulfates.

Maybe I got it wrong. I had a test today that required that I find out the oxidation states of each atom in a molecule. The molecules that contained Pb and S, I didn't know how to figure it out. If there's no shortcut rule that I can follow, I can just draw the molecule and find out the oxidation state of the atom in the molecule. But when the molecule is big, and contains more than one atom that there's no shortcut for, I don't know what to do. I can't draw it, because I can't figure out what atoms attach to the other atoms.

 

[Borek]

Pb is either +2 or +4. As I wrote earlier - in the case of larger molecules they are usually built of ready "blocks" - like sulfate anion, nitrate anion and so on. These have always the same composition and the same charge.

 

[LudusRex]

Drawing molecular diagrams is an important skill for scientists as it allows us to visualize and better understand the structure and composition of molecules. When drawing a molecule like pb2SO4, there are a few rules that can guide you in determining how to arrange the atoms and bonds.

Firstly, it is important to remember that the central atom, in this case Pb, is usually placed in the center of the diagram. The other atoms, in this case, two S and four O atoms, are then attached to the central atom with single bonds. The number of bonds that an atom can form is determined by its valence, which is the number of electrons it needs to gain or lose to have a stable outer shell. In the case of S and O, they have six and four valence electrons respectively, so they can form six and four bonds.

Additionally, it is important to consider the overall charge of the molecule. In the case of pb2SO4, the molecule has a total charge of 2+, which means that it has lost two electrons. This can be represented by placing a positive charge on the central Pb atom.

When it comes to larger molecules with more than three or four atoms, it can be helpful to first draw a rough sketch of the molecule, indicating the central atom and its attached atoms. Then, you can use the valence of each atom to determine the number of bonds it can form and arrange them accordingly.

In some cases, there may be multiple ways to draw a molecule, and it is important to follow the rules mentioned above to ensure accuracy. Overall, drawing molecular diagrams requires practice and familiarity with chemical structures, but with these rules in mind, you should be able to accurately represent molecules of any size.