$$ \text { Write electronic configuration of } \mathrm{Fe}^{2+}, \mathrm{Mn}^{4+}, \mathrm{N}^{3-} \text { and } \mathrm{O}^{2-} \text { ions. } $$

Oxidation states, also known as oxidation numbers, are a method used in chemistry to keep track of electrons in atoms, molecules, and ions. Particularly, they tell us how many electrons an atom has lost, gained, or shared when forming a bond or becoming an ionic species. For instance, in the exercise, iron loses two electrons to become Fe²⁺, indicating it has an oxidation state of +2. Similarly, manganese loses four electrons to form Mn⁴⁺, giving it an oxidation state of +4. On the flip side, nitrogen gains three electrons to become N³⁻, reflecting an oxidation state of -3, and oxygen gains two electrons resulting in O²⁻, which has an oxidation state of -2. Understanding oxidation states is key to predicting the chemical behavior of elements in reactions and forming compounds.

Atomic structure refers to the organization of electrons around the nucleus of an atom. Elements are defined by the number of protons in their nucleus, known as the atomic number. Electrons, which have a negative charge, are found in areas called orbitals around the nucleus. In our exercise, we looked at the atomic structure of Fe, Mn, N, and O. The electron configuration of these atoms changes when they gain or lose electrons. For example, Fe in its neutral state has 26 electrons, but as Fe²⁺ it has only 24. Understanding the atomic structure, including the order in which orbitals are filled, is critical for determining the electron configuration of atoms and ions. It's the first step in predicting how an element will bond with others.

Transition metals, such as iron and manganese in our exercise, are elements that have partially filled d-orbitals. They are located in the middle of the periodic table and are known for their ability to exhibit a variety of oxidation states. This is because the energy levels of the 3d and 4s orbitals are very close, so both can be involved in losing or gaining electrons. Transition metals are also known for forming colorful compounds and for being good conductors of electricity. Understanding how to write the electron configuration for these metals, especially after they form ions, is essential for understanding their chemistry and the types of compounds they can form.

Ionic species are atoms or molecules that have a net positive or negative charge due to the loss or gain of one or more electrons. In our exercise, Fe²⁺ and Mn⁴⁺ are cations (positively charged ions) because they have lost electrons, whereas N³⁻ and O²⁻ are anions (negatively charged ions) because they have gained electrons. The electron configurations of ionic species are critical because they determine the chemical reactivity and the type of bonds the ions can form. In solid form, ionic species constitute ionic compounds, such as salts, which have strong electrostatic attractions between the positively and negatively charged ions.