<div style='margin-bottom: 20px;'> <div style="margin-bottom: 10px; background-color: #f2f2f2; border-radius: 1rem; padding: 10px 20px;"> <h2 style="font-weight: bold; margin-bottom: 3px; font-size: 1.5rem;">Why are zinc, cadmium, and mercury not considered transition metals?</h2> <p style="font-weight: normal; font-size: 1.2rem;">They are not considered transition metals due to their completely filled d orbitals.</p> </div> <div style="margin-bottom: 10px; background-color: #f2f2f2; border-radius: 1rem; padding: 10px 20px;"> <h2 style="font-weight: bold; margin-bottom: 3px; font-size: 1.5rem;">What defines a transition element according to the provided text?</h2> <p style="font-weight: normal; font-size: 1.2rem;">A transition element is defined as one which has incompletely filled d orbitals in its ground state or in any one of its oxidation states.</p> </div> <div style="margin-bottom: 10px; background-color: #f2f2f2; border-radius: 1rem; padding: 10px 20px;"> <h2 style="font-weight: bold; margin-bottom: 3px; font-size: 1.5rem;">What series do the elements with atomic numbers 21 (Sc) to 30 (Zn) belong to?</h2> <p style="font-weight: normal; font-size: 1.2rem;">They belong to the 3d-transition series, known as the first transition series.</p> </div> <div style="margin-bottom: 10px; background-color: #f2f2f2; border-radius: 1rem; padding: 10px 20px;"> <h2 style="font-weight: bold; margin-bottom: 3px; font-size: 1.5rem;">What is the significance of lanthanoid contraction in the context of transition metals?</h2> <p style="font-weight: normal; font-size: 1.2rem;">Lanthanoid contraction refers to the steady decrease in atomic and ionic radii of transition metals as the atomic number increases, due to the filling of 4f orbitals before the 5d orbitals, making the atomic radii of the second and third row of transition elements almost similar.</p> </div> <div style="margin-bottom: 10px; background-color: #f2f2f2; border-radius: 1rem; padding: 10px 20px;"> <h2 style="font-weight: bold; margin-bottom: 3px; font-size: 1.5rem;">How is potassium dichromate prepared from chromate ore?</h2> <p style="font-weight: normal; font-size: 1.2rem;">Potassium dichromate is prepared by fusing chromate ore (FeCr2O4) with sodium carbonate in excess air, followed by a series of reactions involving sodium chromate, sulfuric acid, and potassium chloride.</p> </div> <div style="margin-bottom: 10px; background-color: #f2f2f2; border-radius: 1rem; padding: 10px 20px;"> <h2 style="font-weight: bold; margin-bottom: 3px; font-size: 1.5rem;">Describe the general method for preparing potassium permanganate.</h2> <p style="font-weight: normal; font-size: 1.2rem;">Potassium permanganate is prepared by fusing MnO2 with alkali metal hydroxide (KOH) in the presence of O2 or an oxidizing agent like KNO3, which produces dark green K2MnO4 that undergoes oxidation and reduction to give permanganate.</p> </div> <div style="margin-bottom: 10px; background-color: #f2f2f2; border-radius: 1rem; padding: 10px 20px;"> <h2 style="font-weight: bold; margin-bottom: 3px; font-size: 1.5rem;">What causes the chromates and dichromates to be inter-convertible in aqueous solutions?</h2> <p style="font-weight: normal; font-size: 1.2rem;">The inter-conversion between chromates and dichromates in aqueous solutions depends on the pH of the solution.</p> </div> <div style="margin-bottom: 10px; background-color: #f2f2f2; border-radius: 1rem; padding: 10px 20px;"> <h2 style="font-weight: bold; margin-bottom: 3px; font-size: 1.5rem;">What is Mischmetall and its primary use?</h2> <p style="font-weight: normal; font-size: 1.2rem;">Mischmetall is an alloy consisting mainly of lanthanoid metal (~95%) and iron (~5%) with traces of S, C, Ca, and Al, used in Mg-based alloys to produce bullets, shells, and lighter flint.</p> </div> <div style="margin-bottom: 10px; background-color: #f2f2f2; border-radius: 1rem; padding: 10px 20px;"> <h2 style="font-weight: bold; margin-bottom: 3px; font-size: 1.5rem;">What common oxidation state do lanthanoids exhibit, and what are their magnetic properties compared to actinoids?</h2> <p style="font-weight: normal; font-size: 1.2rem;">+3 oxidation state is most common for lanthanoids, and their magnetic properties are less complex compared to actinoids.</p> </div> </div>