Give reasons for the following (a) \(\mathrm{Mn}^{2+}\) shows the maximum magnetic character among the divalent ions of \(3 d\) -transition series. (b) \(\mathrm{Cu}^{+}\) is diamagnetic but \(\mathrm{Cu}^{2+}\) is paramagnetic. (c) Transition metals have high electrode potential but they are not good reducing agents. (d) Alkali metals are more reactive than transition metals

Understanding the magnetic properties of transition metals is fundamental in the realm of inorganic chemistry, keeping into account that these properties link directly to the electron configuration of the metals. Transition metals, found in the d-block of the periodic table, contain d-orbitals that may or may not be fully filled with electrons. When these d-orbitals have unpaired electrons, the atom displays magnetic properties.

For instance, Mn²⁺, with five unpaired electrons, shows strong magnetic behavior because each unpaired electron has a magnetic moment associated with it. The total magnetic moment results from the sum of these individual magnetic moments, which is why Mn²⁺ has a high magnetic character. This concept is crucial to grasp for students who want to understand why certain transition metals are more magnetic than others.

Moving on to paramagnetism and diamagnetism, these are two types of magnetic properties related to the electron arrangements within an atom. Paramagnetic substances such as Cu²⁺ have one or more unpaired electrons and are weakly attracted by a magnetic field. This is because each unpaired electron generates a magnetic field around itself. Contrastingly, diamagnetic substances, like Cu⁺, have all electrons paired up and slightly repel magnetic fields.

Understanding the difference between these two properties can be made easier by remembering that the presence of unpaired electrons generally means paramagnetism, while substances with all their electrons paired up are diamagnetic. These principles explain the magnetic behaviors of various ions and compounds in magnetic fields.

Electrode potential is another pivotal concept for transition metals and plays a significant role in their chemical behavior. It is a measure of the propensity of a metal to be oxidized or reduced. Transition metals typically have high electrode potentials because they can exist in multiple oxidation states and have a strong ability to stabilize these various states, thanks to their d-orbitals.

Despite the high electrode potentials, transition metals are usually not good reducing agents. This is because their ionization energies are high; removing each successive electron becomes increasingly difficult. Students might wonder why this is the case, and understanding the stability provided by the different accessible oxidation states can clarify this property of transition metals.

When comparing the reactivity of alkali metals to that of transition metals, one immediately notices a stark contrast. Alkali metals, with just one valence electron, are highly reactive. They willingly lose this electron, forming ions with a stable noble gas configuration. This eagerness to give up their valence electron makes them incredibly reactive, even in standard conditions.

Transition metals, however, have higher ionization energies and a more complex electron configuration. This makes them less apt to lose electrons and hence, they demonstrate lower reactivity compared to their alkali counterparts. It's a key point for students to remember, as it significantly affects how these metals behave in chemical reactions and in everyday applications.