Textbook Exercise 9C.3

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Textbook Exercise 9C.3

Postby Adam_Ventura_1H » Sat Dec 05, 2020 2:17 pm

For this question I am being asked to write the formula for the complex compounds. One of the compounds is potassium hexacyanidochromate(III). My question is on the location of where the potassium should be in the formula. Would it be in the front since the potassium is the first thing in the name or does it go at the end like most of the complexes we have seen in class? Or does it even matter if it is in the beginning or the end, as long as it is outside of the brackets?

Stuti Pradhan 2J
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Re: Textbook Exercise 9C.3

Postby Stuti Pradhan 2J » Sat Dec 05, 2020 2:29 pm

The potassium should go at the beginning (before the brackets) because it is a cation. Anions, such as Cl- or F- go after the rest of the name. This is the same idea as you would see in any salt, where the convention is to write the cation first and then the anion (ex. NaCl). In the case of potassium, the rest of the compound is a complex ion with a negative charge, or an anionic complex, so the potassium would go before it.

Hope this helps!

Tae Pasawat 2A
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Re: Textbook Exercise 9C.3

Postby Tae Pasawat 2A » Sun Dec 06, 2020 8:28 am

You should look at the whole compound as an ion in which the potassium is the positively charged metal and the hexacyanidochromate(III) is the non metal. The positively charged metal always comes first in the name of an ionic compound: such as sodium chloride.

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Re: Textbook Exercise 9C.3

Postby Dylan_Nguyen_2C » Sun Dec 06, 2020 8:45 pm

When naming compounds, the cation is named first and the anion comes after. So in this example, because K has a positive charge, the K3 would be placed in front of the rest of the compound. Another example is salt, NaCl, where the Na+ comes first and the Cl- comes after. Hope this helps

Megan Lu 3D
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Re: Textbook Exercise 9C.3

Postby Megan Lu 3D » Sun Dec 06, 2020 8:58 pm

Hi! Like others have said above, the potassium should be located at the beginning, in front of the brackets, because it is a cation (more specifically, a positively-charged metal) with a 1+ charge. Potassium hexacyanidochromate (III) is a compound, so we name the cation first and then the anion.

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