Order of Elements When Writing Out a Compound

[AArmellini_1I]

So I know this may seem like a silly question, but honestly my chemistry knowledge is pretty rusty. While working on some homework problems there were multiple times where I solved for the amount (in mols) of each element (which I could do). But what I couldn't figure out was how to write the product based on that information. For example, if you had a mole of Os, 4 moles of C, and 4 moles of O, how do you know that the product is suppose to be arranged as such: OsC4O4? At first I thought maybe it went by alphabetical order but this exampled proved me wrong. And help would be greatly appreciated!

[Zaynab Hashm 2I]

Typically,if carbon is present it comes first, then hydrogen, and then the others alphabetically. Cations are also written first before anions, so positive before negative in ionic compounds. I believe in the one you mentioned it's C, O, then Os.

[Connor Ho 1B]

Typically,if carbon is present it comes first, then hydrogen, and then the others alphabetically. Cations are also written first before anions, so positive before negative in ionic compounds. I believe in the one you mentioned it's C, O, then Os.

I agree. I think it's called the Hill System, where the carbons always come first and then hydrogens and then everything else. So in reality, the compound you're looking at should be C₄O₄Os.

[Sara Richmond 2K]

I am not sure that the order of the elements will matter too much as professor Lavelle has not reviewed this in class. However, in organic chemistry carbon comes first, followed by hydrogen, followed by oxygen, followed by everything else.

[Natalie Wang 1B]

I actually asked my TA, and he said that for now, we don't need to know how to write chemical formulas correctly. We also don't need to know how to write out chemical formulas from just the compound's name for our first test! Apparently, we'll be learning the basics of chemical formulas and nomenclature later in the class.

[Lizette Noriega 1H]

According to the TAs, this information will be given to us. The only situation in which we'll have to write out the compounds will be for questions that include combustion/oxidation/metabolism.

[ranqiao1e]

Also, I think the order doesn't matter unless the question explicitly asks for it. It's not as strict as the other rules, as long as you can draw the right chemical structure from the formula.

[Catherine Daye 1L]

I think it's supposed to be in alphabetical order (ex. hydrogen, carbon, chlorine, oxygen). After taking chem for a while and getting used to seeing a bunch of different compounds, putting them in order will become automatic. :)

[Lauren Sanchez 3D]

I was also a little confused with this topic too, but I was informed that the question itself can present the elements in the correct order already (at least for this first test)