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Ionic compounds are chemical substances made up of positively charged ions called cations and negatively charged ions called anions. These ions are held together by the strong electrostatic forces known as ionic bonds. In an ionic compound, the total positive charge must balance the total negative charge, leading to a neutrally charged compound.

Take the example of silver chloride from the exercise. Silver (Ag) serves as the cation with a +1 charge, while chloride (Cl) functions as the anion with a -1 charge. When they combine to form a compound, the charges cancel out, resulting in an uncharged, neutral ionic compound of AgCl.

The variety of ionic compounds is vast, and they commonly form crystalline solids which exhibit high melting and boiling points due to the strength of the ionic bonds holding the lattice structure together.

Chemical nomenclature is a systematic way of naming chemical substances. It's like the language of chemistry that provides a standard procedure for naming compounds in order to avoid confusion. For ionic compounds, such as silver chloride, the name typically starts with the metal (silver) followed by the name of the nonmetal with its ending changed to '-ide'; hence, we get 'chloride'.

This system is guided by rules set out by the International Union of Pure and Applied Chemistry (IUPAC), ensuring that each chemical name reflects the composition of the substance it represents. Naming compounds correctly involves understanding the valency of elements, which leads to the appropriate use of prefixes and suffixes in the case of more complex compounds, including polyatomic ions.

The valency of an element is a measure of its ability to bond with other elements. It is determined by the number of electrons an atom needs to lose, gain, or share to achieve a full outer shell, which is often referred to as the 'octet rule'. The valency essentially tells us how many bonds an element can form or the ratio in which it combines with other elements.

In our given example of silver chloride, silver has a valency of 1, indicating it can form one bond and typically lose a single electron to become Ag+. Chlorine, on the other hand, also displays a valency of 1, as it tends to gain one electron to complete its outer shell, becoming Cl-.

When writing chemical formulas, it is essential to balance the valencies to ensure a neutral compound. By matching the number of positive and negative charges, you can determine in what ratio atoms will combine to form a compound, as seen in the simple 1:1 ratio of Ag+ to Cl- in AgCl.