Name a member of the lanthanoid series which is well known to exhibit `+4` oxidation state.

(i) Name the element of 3d transition series which shows maximum number of oxidation states. Why does it show so ? (ii)Which transition metal of 3d series ha positive E^(@)(M^(2+)//M) value and why ? (iii) Out of Cr^(3+) and Mn^(3+) , which is a stronger oxidizing agent and why ? (iv) Name a member of the lanthanoid series which is well known to exhibit + 2 oxidation state. (v) Complete the following equation : MnO_(4)^(-) + 8H^(+) + 5e^(-) to .

Name a member of the lanthanoid series which is well known to exhibit +2 oxidation state.

(i)with reference to structural variability and chemical reactivity write the differences between lanthanoids and actinoids (ii) Mame a member of the lanthanoid series which is well known to exhibit +4 oxidation state (iii) Complete the following equation : MnO_(4)^(-)+8H^(+)+5e^(-)rarr (iv) out of Mn^(3+) and Cr^(3+) which is ore paramagnetic and why? Atomic nos : Mn =25 Cr =24

Name the following: (a) A transition metal which does not exhibit variation in oxidation state in its compounds. (b) A compound where the transition metal is the +7 oxidation state. (c) A member of the lanthanoid series which is well known to exhibit +4 oxidation state. (d) Ore used in the preparation of Potassium dichromate.

(i) Which transition element in 3d series has positive E_(M^(2+//)M)^(@) value and why ? (ii) Name a member of lanthanoid series which is well known to exhibit to exhibit +4 oxidation state and why? (b) Account for the following : (i) The highest oxidation state is exhibited in oxoanions of transition metals. (ii) HCl is not used to acidify KMnO_(4) solution. (iii) Transition metals have high enthalpy of atomisation.

Lanthanoids and actinoids are f-block elements in which the last electron enters the anti-penultimate energy level. The most common oxidation state of lanthanoids is +3, though +2 and +4 oxidation states are exhibited by some of the elements. In lanthanoid series, there is a progressive decrease in atomic and ionic radii, known as lanthanoid contraction. Unlike lanthanoids, actinoids show a large number of oxidation states. Name an element of lanthanoid series, which is known to show +4 oxidation state. Is it a strong oxidising agent or reducing agent?