Final answer:
The formula and charge of the oxoanion in acetate (ethanoate) is CH3COO- with a charge of -1, in manganate is MnO42- with a charge of -2, and in nitrate is NO3- with a charge of -1.
Step-by-step explanation:
To give the formula and charge of the oxoanion in each of the listed compounds, we need to identify the polyatomic ion which is present in the compound and provide its corresponding formula and charge.
Acetate (ethanoate) - The oxoanion formula is CH3COO- and it carries a negative one (-1) charge.
Manganate - The oxoanion formula is MnO42- with a negative two (-2) charge.
Nitrate - The oxoanion formula is NO3- and it carries a negative one (-1) charge.
To predict the formula of the ionic compound formed between the lithium ion and the peroxide ion, O22-, we must consider the charges of the ions. Lithium has a charge of +1, resulting in the compound formula Li2O2 when combined with the peroxide ion, which has a negative two (-2) charge.
This results from the charge balancing rule: transpose only the number of the positive charge to become the subscript of the anion and vice versa, then reduce to the lowest ratio. For Li2O2, the subscripts are already in the lowest whole numbers, hence no reduction is necessary.
Similarly, when combining sodium ions (Na+) with oxalate ions (C2O42-), the formula Na2C2O4 is used to accurately represent the 2:1 ratio of sodium to oxalate ions, without reducing the subscripts since the empirical formula would not accurately depict the oxoanion.
The formula for lithium peroxide is Li2O2, following a charge balancing rule without reduction in subscripts. For sodium oxalate, the correct formula is Na2C2O4, representing the actual ratio without reducing to empirical subscripts.