Question

Anyone knows why do they put that bracket and a Roman Numeral in the name of the compounds?​

Answer 1

Answer:

Hello Mecats,

The answer for your question is :

Explanation:

We put brackets if there are any complex ion, we put them to show how many complex ion does one compound consists and if you want to remove the bracket, For example: Iron [III] Hydroxide you can write it as Fe(OH)3..

Hope this helps you.

Answer 2

These Roman Numeral represent oxidation numbers or valency.

For eg:- It's given that Copper [ III ], so these Roman Numerals, represent the valency of copper.

___________________________

Additional Information:-

The symbolic representation of a molecule of a compound is called a chemical formula.

Writing a chemical formula:-

• Write the symbols of the two radicals side by side, first radical in left side and second radical in right side.
• If necessary, divide the valencies by the HCF, to get a simple ratio.
• Shift the valencues cross wise, to the lower right of the radicals. You can also do cross multiplying.

Eg:-

Compound:-

Sodium carbonate

NA¹CO⅔

Symbol with valency:-

NA¹CO⅔

Criss cross:-

$\large\sf NA \: \: \: \: \: \: CO \\ ↙ \: \: \: \: ↘ \\ \sf 1 \: \: \: \: \: \: \: \: \: \: \: 2$

Formula:-

$\large \sf Na_2CO_3$