Give the oxidation number of the underlined atoms in the following molecules and ions: (a) \(\mathrm {\underline{C l}}\mathrm{F}\), (b) \(\underline{I}$$\mathrm{F}_{7}\), (c) \(\underline{C}$$\mathrm{H}_{4}\),(d) \(\underline{C}_{2}$$\mathrm{H}_{2}\),(e) \(\underline{C}_{2}$$\mathrm{H}_{4}\),(f) \(\mathrm{K}_{2}$$\underline{Cr}$$\mathrm{O}_{4}\),\((\mathrm{g}) \mathrm{K}_{2}$$\underline{Cr}_{2}$$\mathrm{O}_{7}\),(h) K\(\underline{M n}$$\mathrm{O}_{4}\),(i) \(\mathrm{NaH}$$\underline{C}$$\mathrm{O}_{3}\),(j) \(\underline{L i}_{2}\),(k) \(\mathrm{Na}$$\underline{I}$$\mathrm{O}_{3}\)(1) \(\mathrm{K}$$\underline{} \underline{0}_{2}\), \((\mathrm{m}) \underline{\mathrm{PF}}_{6}^{-}\),(n) \(\mathrm{K}$$\underline{Au}$$\mathrm{Cl}_{4}\).

Oxidation states, also known as oxidation numbers, provide insight into the electronic structure of compounds. They signify the hypothetical charges that atoms would have if the compound was composed of ions. This concept is fundamental in understanding the electron transfer in redox reactions.

To assign oxidation numbers, one must use established rules: elemental forms (such as \text{O}\(_2\) or \text{S}\(_8\)) have an oxidation number of 0, for ions, it's the ion charge, and for atoms in compounds, values are assigned usually beginning with the most electronegative elements. In compounds, oxygen is usually assigned a -2 oxidation state and fluorine is always -1 due to its high electronegativity.

Incorrect assignments can lead to confusion, especially when dealing with complex molecules or polyatomic ions. For novice chemistry students, associating familiar elements like oxygen and fluorine with their common oxidation states can be a stepping stone for understanding more complex systems.

Chemical nomenclature refers to the system of names used to identify chemical substances. These names are meticulously crafted to impart specific information about the chemical composition and structure of the compound. Nomenclature is guided by rules established by international bodies like the International Union of Pure and Applied Chemistry (IUPAC). Understanding these rules helps to undo the puzzles of chemical formulas, turning them into understandable language.

For example, the compound K\(_2\)Cr\(_2\)O\(_7\) is named potassium dichromate, indicating the presence of potassium (K), chromium (Cr), and oxygen (O). Each element's subscript denotes how many atoms are present, crucial for determining oxidation states. Students often struggle with nomenclature while learning chemistry, but mastering this language is essential for clear communication and deeper comprehension of chemical phenomena.

Redox reactions are chemical processes that involve the transfer of electrons between species. These reactions are characterized by changes in the oxidation states of one or more elements involved in the reaction. Understanding the concept of oxidation states is key to identifying and balancing redox reactions.

A classic example involves the reaction between hydrogen gas and oxygen gas to form water. Hydrogen goes from an oxidation state of 0 to +1, while oxygen goes from 0 to -2. Oxidation states offer clues about which element is being oxidized and which is being reduced. It's often in redox reactions where the subtleties of oxidation states are critical, such as when compounds with elements in high oxidation states (like \text{KMnO}\(_4\)) act as powerful oxidizing agents.

Developing a strong understanding of oxidation states and redox reactions is invaluable for students, allowing them to predict the course of chemical reactions and analyze the resultant changes in chemical structures. Simplifying complex redox systems into half-reactions, examining the flow of electrons, and applying the concept of conservation of charge are critical skills honed during the study of these transformative chemical events.