Question

Correct each of the following formulas: (a) Barium oxide is \(\mathrm{BaO}_{2}\). (b) Iron(II) nitrate is \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}\) (c) Magnesium sulfide is \(\mathrm{MnSO}_{3}\). (d) Potassium iodide is \(\mathrm{P}_{2} \mathrm{I}_{3}\).

Short answer

(a) \( \text{BaO} \), (b) \( \text{Fe(NO}_3\text{)}_2 \), (c) \( \text{MgS} \), (d) \( \text{KI} \).

Step-by-step solution

Correct Barium Oxide Formula

Barium forms a +2 ion and oxide forms a -2 ion. Therefore, the correct formula for barium oxide is \(\text{BaO}\) since the charges balance out as \( \text{Ba}^{2+} \text{O}^{2-} \).

Correct Iron(II) Nitrate Formula

Iron(II) means iron has a +2 charge, and nitrate (NO3) has a -1 charge. The correct formula is \(\text{Fe(NO}_3\text{)}_2\), balancing the charges as \( \text{Fe}^{2+} (\text{NO}_3^{-})_2 \).

Correct Magnesium Sulfide Formula

Magnesium has a +2 charge while sulfide has a -2 charge. The correct formula for magnesium sulfide is \( \text{MgS} \) since \( \text{Mg}^{2+} \text{S}^{2-} \) balance each other.

Correct Potassium Iodide Formula

Potassium has a +1 charge and iodide has a -1 charge. The correct formula for potassium iodide is \(\text{KI}\), as the charges from \( \text{K}^{+} \text{I}^{-} \) balance each other.

Key concepts

Ionic Charges

Understanding ionic charges is essential for forming correct chemical formulas.
Ionic charges result from an atom either losing or gaining electrons.
This process forms ions, which are charged particles.
Remember these key points for ionic charges:

• Metal atoms commonly lose electrons to form positive ions, known as cations
• Non-metal atoms tend to gain electrons, forming negative ions, known as anions

For example, barium (Ba) forms a +2 ion because it loses two electrons, while oxygen (O) forms a -2 ion because it gains two electrons.
Therefore, barium oxide (BaO) balances out with one Ba²⁺ and one O^2-.
Always make sure the total positive charge equals the total negative charge in a compound.

Chemical Nomenclature

Chemical nomenclature is the systematic naming of chemical compounds.
Correct naming helps you identify compounds and understand their composition.

• Ionic compounds are named with the cation first, followed by the anion
• The cation retains its elemental name, while the anion's name ends in '-ide' if it's a simple ion, or uses its polyatomic name if applicable
• Transition metals’ ionic states are indicated by Roman numerals

For instance, in iron(II) nitrate, iron (Fe) has a +2 charge (Fe²⁺), and nitrate (NO₃^-) contains one nitrogen and three oxygen atoms with an overall -1 charge.
Hence, Fe(NO₃)₂ indicates two nitrates are needed to balance the +2 charge of one iron ion.
Understanding these rules simplifies writing and correcting chemical formulas.

Formula Correction

Correcting chemical formulas involves ensuring ionic charges balance and applying proper nomenclature rules.
Here are steps to correct formulas effectively:

• Identify the ions and their charges
• Ensure the total positive charges equal the total negative charges
• Apply nomenclature rules properly

Using the given problems as examples:

• For Barium oxide, since Ba²⁺ and O^2- both have charges of 2, the balanced formula is BaO
• For Iron(II) nitrate, since Fe²⁺ and NO₃^-, you need two NO₃^- ions to balance one Fe²⁺, making the correct formula Fe(NO₃)₂
• For Magnesium sulfide, Mg²⁺ and S^2- balance out as MgS
• For Potassium iodide, K⁺ and I^- each have a charge of 1, making the formula KI

Properly balancing the ionic charges and following systematic naming conventions ensures accurate chemical formulas.