Ordering Elements When Writing Formulas

[Kassandra Javier 2D]

How do you determine what order the elements should go in when writing an empirical or molecular formula? For example, how do you know it is supposed to be C6H8O6 and not O6H8C6?

[Sadhana Jeyakumar 2J]

I have the same question. I know in high school, my chemistry teacher told us that carbon is always listed first, then hydrogen, and then any other elements. I don't remember though if these "other elements" are supposed to be listed in a specific order, or what you would do if there are no carbon or hydrogen atoms in the formula.

[Justin_Choo_3J]

Hello all,

Chemistry follows the "Hill System Order" such that when writing equations, carbon is noted first, then hydrogen and all remaining elements are listed in alphabetical order. If carbon is not present, all elements, including hydrogen must be listed in alphabetical order. Here is a helpful link for more info and examples: www.web.cas.org/training/stneasytips/su ... mula1.html. Hope this helps :)

[Emily Quill 2H]

Hi! That's very helpful. I was told Carbon usually goes first followed by Hydrogen, but that we would not need to really worry about that for now at the beginning of this course.

[Alex_Lee_1K]

Hello,

Thanks for the resource, I was always under the impressions that everything just had to be alphabetical. Thanks for the clarification!