Understanding Polyatomic Ion Charges and Number of Oxygen

In summary, the conversation discusses the challenges of naming polyatomic ionic compounds and the struggle to remember charges and number of oxygens associated with these ions. While systematic naming exists, it is not commonly used and it is better to memorize the common names, which are often inaccurate and based on historical reasons. The general rule for naming is that "-ate" indicates the highest oxidation state if it is less than +7, with additional specifications for multiple ions of the same oxidation state.
  • #1
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I have recently started self studying chemistry and I am at the point where I'm learning to name chemicals given chemical formulas and vice versa. (Like Iron (III) Oxide --> Fe2O3). I am having trouble with doing this process for polyatomic ionic compounds. I can't seem to remember some the charges and the number of oxygen associated with the PA ion. I learned about PA ion naming just today and I could probably memorize the charges and number of oxygens pretty easily but that doesn't give me satisfaction. Is there any method to derive these charges and number of oxygens?

Ex - going from Sulfate to SO4 2- without memorizing the 4 or 2- charge, just knowing Sulfur and "-ate"
 
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  • #2
Systematic naming of polyatomics exists, but virtually nobody uses it in the real life. For historical reasons common names are full of inaccuracies and ad hoc rules, as they evolved with our increasing knowledge. They are far from being systematic and logical and it is better to memorize them.
 
  • #3
Not easy.
General rule is:
"-ate" is the highest oxidation state if less than +7
There are additional specifications of "ortho" and "meta" if there are several ions of the same oxidation state. But these are commonly omitted if one species is common.
 

1. What is a polyatomic ion?

A polyatomic ion is a charged particle composed of two or more atoms bound together by covalent bonds. It has an overall charge due to the gain or loss of electrons.

2. How do you determine the charge of a polyatomic ion?

The charge of a polyatomic ion is determined by the number of valence electrons in the atoms that make up the ion. If the ion has more electrons than protons, it will have a negative charge, and if it has more protons than electrons, it will have a positive charge.

3. Why do polyatomic ions have different numbers of oxygen atoms?

The number of oxygen atoms in a polyatomic ion depends on the chemical formula and the charge of the ion. The oxygen atoms are added or subtracted to balance out the overall charge of the ion.

4. What is the significance of the number of oxygen atoms in a polyatomic ion?

The number of oxygen atoms in a polyatomic ion affects the ion's properties, such as its reactivity and stability. It also determines the ion's overall charge and its ability to form bonds with other atoms.

5. How can I remember the charges and number of oxygen atoms for common polyatomic ions?

One way to remember the charges and number of oxygen atoms for common polyatomic ions is by using mnemonics or flashcards. Another helpful tip is to understand the patterns and trends in the charges and number of oxygen atoms for different families of polyatomic ions.

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