Write the formulas of (a) magnesium \(\omega\) xide (magnesia); (b) calcium phosphate (the major inorganic componcnt of bones); (c) aluminum sulfate; (d) calcium nitride.

Understanding oxidation states is crucial when working with chemical compounds. An oxidation state, often signified as the Greek letter \(\omega\), is the hypothetical charge an atom would have if all its bonds to atoms of different elements were fully ionic. This concept is particularly helpful when writing chemical formulas because it allows us to balance the total charges in a molecule or ionic compound.

In the given exercise, the oxidation state of magnesium in magnesium oxide is +2. Oxygen typically has an oxidation state of -2. Recognizing these states assists in predicting how atoms will combine to form compounds. For instance, magnesium and oxygen form a neutral ionic compound (\(MgO\)) because the +2 charge from magnesium balances the -2 charge from oxygen.

Ionic compounds are formed from positive and negative ions that are held together by strong electrostatic forces, known as ionic bonds. These ions are usually metal cations (positive ions) and non-metal anions (negative ions). Ionic compounds are generally composed of ions that combine in ratios that result in an overall neutral charge.

When creating the formula for an ionic compound such as calcium phosphate (\(Ca_3(PO_4)_2\)), we must consider the charge of each ion to ensure that the total positive and negative charges are balanced. For example, calcium has a +2 charge while phosphate has a -3 charge. To achieve a neutral compound, we need three calcium ions to balance the charge of two phosphate ions.

Polyatomic ions are charged species composed of two or more atoms covalently bonded, or of a metal complex that acts as a single unit in a compound. The charge of polyatomic ions must be taken into account when they are part of ionic compounds. Phosphate (\(PO_4^{3-}\)) and sulfate (\(SO_4^{2-}\)) are examples of such ions encountered in our exercise.

Understanding how to balance the charges of polyatomic ions with other cations and anions is essential for writing correct chemical formulas. For instance, aluminum sulfate is composed of the aluminum cation (\(Al^{3+}\)) and the sulfate anion. To form a neutral compound (\(Al_2(SO_4)_3\)), two aluminum ions are paired with three sulfate ions. This ensures the net charge of the compound is zero, satisfying the requirement for charge neutrality.

Chemical nomenclature is the systematic naming of chemical compounds and is vital for clear communication in science. The nomenclature for ionic compounds involves combining the names of the positive and negative ions. The cation (positive ion) is named first, followed by the anion (negative ion), with the latter often ending in '-ide' if it's a single element or a distinct suffix when it is a polyatomic ion, like '-ate' or '-ite'.

The formulas of chemical compounds like calcium nitride (\(Ca_3N_2\)) follow the naming convention where the metal cation name precedes that of the non-metal anion. The subscript numbers in the chemical formulas tell you the ratio of atoms or polyatomic ions needed to balance charge. Understanding chemical nomenclature not only simplifies the process of writing chemical formulas but also enhances communication and reduces confusion among scientists and students.