Write the formula of the compound that will be formed between these elements: (a) \(\mathrm{Al}\) and \(\mathrm{S}\) (d) Sr and \(O\) (b) \(\mathrm{H}\) and \(\mathrm{F}\) (e) Cs and P (c) \(\mathrm{K}\) and \(\mathrm{N}\) (f) \(\mathrm{Al}\) and \(\mathrm{Cl}\)

Understanding ion charges is crucial when writing chemical formulas. Ion charges, also known as ionic charges, refer to the electrical charge that an atom possesses when it gains or loses electrons during the formation of ions. Elements in the periodic table can have more than one possible ion charge, but they often have a common or preferred state.

For example, alkaline earth metals such as magnesium and calcium typically have a 2+ charge because they tend to lose two electrons to achieve a stable electron configuration. Similarly, halogens like chlorine and fluorine usually assume a 1- charge by gaining an electron. Knowing the common ion charges helps us predict how elements will combine to form compounds.

Balancing ionic charges is key to determining the correct formula for a chemical compound. The principle of charge balance states that the total positive charge must equal the total negative charge in a neutral compound. This is achieved by combining ions in a ratio that makes the overall charge zero.

To illustrate, if we have a metal ion with a 2+ charge and a nonmetal ion with a 1- charge, we would need two nonmetal ions to balance the charge of one metal ion, resulting in a formula of MX2, where M represents the metal ion and X represents the nonmetal ion.

When ions with opposite charges come together, they form a chemical compound. In ionic compounds, cations (positive ions) and anions (negative ions) are held together by ionic bonds - the electrostatic forces of attraction between ions of opposite charges. To write the chemical formula of a compound, one must know the ion charges and how many of each ion is needed to achieve a neutral charge.

In the compound formation, the least common multiple of the ionic charges can be used to find the correct ratio of ions. For instance, for aluminum (3+ charge) and sulfur (2- charge), we find the least common multiple of 3 and 2 is 6, indicating that we need two Al ions and three S ions to balance out, resulting in Al₂S₃.

The oxidation state, also known as the oxidation number, is a concept from redox chemistry that pertains to the degree of oxidation of an atom in a compound. It is a theoretical charge that an atom would have if all its bonds were purely ionic. The oxidation state helps to determine the formula of compounds, especially when dealing with transition metals, as they can exhibit multiple oxidation states.

For elements in main groups, the common oxidation states generally correspond to the group number for metals and group number minus eight for non-metals. This guideline assists in inferring the likely oxidation states when writing chemical formulae for compounds.