Fill the blanks in the following table. $$\begin{array}{|c|c|c|c|}\hline \text { Cation } & \text { Anion } & \text { Formula } & \text { Name } \\\\\hline & & & \text { Magnesium bicarbonate } \\\\\hline & & \mathrm{Sr} \mathrm{Cl}_{2} & \\\\\hline \mathrm{Fe}^{3+} & \mathrm{NO}_{2}^{-} & & \\ \hline & & & \text { Manganese(II) chlorate } \\\\\hline & & \mathrm{SnBr}_{4} & \\\\\hline \mathrm{Co}^{2+} & \mathrm{PO}_{4}^{3-} & & \\\\\hline \mathrm{Hg}_{2}^{2+} & \mathrm{I}^{-} & & \\\\\hline & & \mathrm{Cu}_{2} \mathrm{CO}_{3} & \\\\\hline & & & \text { Lithium nitride } \\\\\hline \mathrm{Al}^{3+} & \mathrm{S}^{2-} & & \\\\\hline\end{array}$$

Understanding the key players in an ionic compound—namely cations (positively charged ions) and anions (negatively charged ions)—is crucial for mastering chemical nomenclature. Cations are typically metal ions or ammonium (\(NH_4^+\)), while anions are nonmetals or polyatomic ions.

Identifying cations and anions in a compound is straightforward when you know the charges associated with different elements and polyatomic ions. For instance, in the compound magnesium bicarbonate, \(Mg^{2+}\) is the cation and \(HCO_3^-\) is the anion. For transition metals, the charge is usually indicated in the compound's name, such as in iron(III) nitrite where iron(III) indicates a cation with a +3 charge.

• Metals usually form cations with a positive charge equal to their group number in the periodic table.
• Nonmetals typically gain electrons to become anions with a negative charge that is numerically equal to eight minus their group number.
• Polyatomic ions, like \(NO_2^-\), \(PO_4^{3-}\), or \(ClO_3^-\), have their own characteristic charges.

Learning the common charges for the elements and polyatomic ions can greatly simplify the process of identifying which is the cation and which is the anion in a compound.

Writing the chemical formula of an ionic compound requires a clear understanding of the charges on the cations and anions involved. The overarching rule is that the total positive charge must balance the total negative charge, resulting in a neutral compound.

For example, to write the formula for strontium chloride, we combine the strontium cation (\(Sr^{2+}\)) and the chloride anion (\(Cl^-\)) in such a ratio that the charges cancel out: \(SrCl_2\). Similarly, aluminum sulfide is formed by combining aluminum cation (\(Al^{3+}\)) with sulfide anion (\(S^{2-}\)), leading to the formula \(Al_2S_3\).

If you encounter a polyatomic ion (like bicarbonate \(HCO_3^-\) or phosphate \(PO_4^{3-}\)), remember it acts as a single unit. Always use parentheses if you need more than one of a particular polyatomic ion, as seen in magnesium bicarbonate \(Mg(HCO_3)_2\) and cobalt(II) phosphate \(Co_3(PO_4)_2\).

To hone this skill, remember these tips:

• Identify the cation and anion, along with their respective charges.
• Use the cross-multiplication method to balance the charges.
• Write the resulting formula with the lowest whole number ratio of ions.

Naming inorganic compounds follows specific, but simple rules designed around the type of compound and the elements it contains. For binary compounds (involving just two different elements), the name begins with the cation and ends with the anion. The anion's name is modified to end in '-ide', such as lithium nitride (\(Li_3N\)) where lithium is the cation and nitride is the anion.

When dealing with transition metals, which can have multiple possible charges, the cation's charge is indicated in parentheses using Roman numerals. For example, Iron(III) Nitrite reveals that iron has a +3 charge in that particular compound.

Polyatomic ions have special names that must be memorized, such as nitrate (\(NO_3^-\)), sulfate (\(SO_4^{2-}\)), and phosphate (\(PO_4^{3-}\)). Thus, compounds like manganese(II) chlorate (\(Mn(ClO_3)_2\)) involve the metal's common name with a Roman numeral charge indicator and the name of the polyatomic ion.

Remember these tips for inorganic compound naming:

• For simpler binary inorganic compounds, use the 'root' of the nonmetal's name plus an '-ide' ending.
• Include the metal's charge as a Roman numeral for transition metals with more than one possible charge.
• Memorize common names and formulas of polyatomic ions, as they remain unchanged in compound names.

Practice identifying the types of cations and anions in various compounds to enhance your competence in naming inorganic compounds.