Question

What is the chemical formula for mercury (I) nitrate?

Answer 1

The nomenclature of organic and inorganic chemical compounds is governed by the "international union of pure and applied chemistry". The name of a compound should be systematic and be able to depict and determine the unambiguous formula of a chemical compound.

Complete answer:
Some rules for naming simple inorganic chemical compound are
- The name of the cation or the compound with a positive charge is usually simply the name of the element and followed by the name of the anion.
Hence in mercury (I) nitrate, the cation is mercury (Hg).
- Compounds having more than a single positive charge, or cations are labeled using roman numbers after the name of the cation in brackets.
So, the charge on Hg in mercury (I) nitrate is +1 i.e., $M{{g}^{1+}}$
- Polyatomic anions containing oxygen or oxyanions have suffix -ite for a lesser quantity of oxygen and suffix -ate for the greater quantity of oxygen.
So, nitrate ions have 3 oxygen atoms.
Now, nitrate ions are obtained by removing 1 ${{H}^{+}}$ proton from nitric acid ($HN{{O}_{3}}$). So, the charge on nitrate ions is -1.
Hence the anions can be written as $NO_{3}^{1-}$.
Now, the compound mercury (I) nitrate can be written as $H{{g}^{1+}}{{(N{{O}_{3}})}^{1-}}$.
Now, the charge on the compound mercury (I) nitrate can be neutralized if there is 1 atom of mercury ($M{{g}^{1+}}$) cation and 1 molecule of nitrate ($NO_{3}^{1-}$) anion.
Hence, the formula of mercury (I) nitrate is $HgN{{O}_{3}}$ or $H{{g}_{2}}{{(N{{O}_{3}})}_{2}}$.

Note:
It should be noted that ions can be polyatomic. Cations (which are usually metals and positively polyatomic ions) are named before anions (which are usually non-metals and negative polyatomic ions).
Also, some of the prefixes and suffixes indicating oxidation numbers according to the older system are