## Chemical formula?

Nahal 1F
Posts: 50
Joined: Fri Jun 23, 2017 11:39 am

### Chemical formula?

How do you find the chemical formula of compounds?

For example, chronium(III) and manganese(II)

Timothy Kao 1B
Posts: 28
Joined: Fri Jun 23, 2017 11:39 am

### Re: Chemical formula?

Section D in fundamentals goes over how to derive the chemical formula from a compound's name.

mayapartha_1D
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

### Re: Chemical formula?

Hi!

You usually will not have to find a chemical formula without any given values. Metals, gases, etc. have different characteristics that make them easier to figure out; which is listed in the book.

Hope this helped.

Katie Lam 1B
Posts: 52
Joined: Fri Sep 29, 2017 7:06 am

### Re: Chemical formula?

The Roman numerals refer to the charge on that atom. In this case, chromium has a +3 charge so you know how to write the formula for a neutral molecule.

Kyung_Jin_Kim_1H
Posts: 53
Joined: Thu Jul 27, 2017 3:00 am

### Re: Chemical formula?

Hi! In addition to what others have mentioned above, it's helpful to know the charges of the common elements on the table. For example, Group I all has a +1 charge, Group II has +2, etc. Once you know the charges of the elements in your compound, you can find out how many atoms of an element are in it. (Ex. Copper (II) Chloride --> Copper has +2 charge, chloride has -1 charge, the molecule has a net charge of 0, so there must be 2 chlorides --> CuCl2 ).

Jean Mok 3K
Posts: 22
Joined: Sat Jul 22, 2017 3:01 am

### Re: Chemical formula?

The chemical formula of compounds can be created using rules that can be generalized used on patterns. These rules can be found in the fundamentals part of the textbook (section D). The two things you ask of, however, are cations and perhaps you mean to ask how to find the charges for them. For transition metals, the roman numeral will be the charge. Hope this helps!