Which of the following is not a transition element ?

The maximum oxidation state of osmium is

Which of the following ion is colourless in aqueous solution ?

Which metal has highest density ?

Permanent magnets are generally made of alloys of

Predict which of the following will be coloured in aqueous solution.

Ti³⁺, V³⁺, Cu⁺, Sc³⁺, Mn²⁺, Fe³⁺ and Co^2+.

Give reason for each.

Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?

Assign reasons for each of the following :

(i) Transition metals generally form coloured compounds.

(ii) Manganese exhibits the highest oxidation state of +7 among the 3d series of transition elements.

Describe the steps involved in the preparation of either potassium dichromate from sodium chromate or potassium permanganate from manganese dioxide.

Why hydrated copper sulphate is blue while anhydrous copper sulphate is white ?

Explain the following:

(i) The transition elements have great tendency for complex formation.

(ii) There is a gradual decrease in the atomic sizes of transition elements in a series with increasing atomic numbers.

(iii) Lanthanum and Lutetium do not show colouration in solutions.

   (At. No.: La=57, Lu=71)

(a) Comlete the following chemical equations for reactions in aqueous media:

  (i) Cr₂O₇^2-+H⁺+Fe²⁺\(\longrightarrow \)

  (ii) MnO₄^-+I^-+H⁺\(\longrightarrow \)

(b) How many unpaired electrons are present in Mn²⁺ ion (At. no. of Mn =25)? How does it influence magnetic behaviour of Mn²⁺ ions?

Identify the first row transition metal ions which have outer electronic configurations of 3d⁴ and 3d⁶ and describe their oxidation states. 

Complete the following reactions:

(a) Cr₂O₇^2-+14H⁺+6e^-\(\longrightarrow \).......... +7H₂O

(b) CrO₄^2-+..........\(\rightleftharpoons \)........\(\rightleftharpoons \).......+H₂O

(c) MnO₄^-+2H₂O+3e^- \(\overrightarrow { medium } \)........ +4OH^-

Co~pare the chemistry of the actinoids with that of lanthanoids with reference to the following :
(i) Electronic configuration
(ii) Oxidation states
(iii) Chemical reactivity

(a) Comlete the following chemical equations:

(i) Cr₂O₇^2-(aq) +H₂S(g) +H⁺(aq) \(\longrightarrow \) 

(ii) Cu²⁺(aq) +I^-(aq) \(\longrightarrow \)

(b) How would you account for the following?

(i) The oxidising power of oxoanions are in the order

VO₂⁺ < Cr₂O₇^2- < MnO₄^-

(ii) The third ionization enthalpy of manganese (Z=25) is exceptionally high.

(iii) Cr²⁺ is a stronger reducing agent than Fe²⁺.

Compare the general characteristics of the first series of the transition metals with those of the second and third columns. Give special emphasis on the following points:

     (i) electronic configurations,

     (ii) oxidation states,

     (iii) ionisation enthalpies and 

     (iv) atomic sizes.

The elements of \(3d\) transition series are given as:

Sc Ti V Cr Mn Fe Co Ni Cu Zn

Answer the following:

(i) Write the element which is not regarded as a transition element. Give reason.

(ii) Which element has the highest m.p?

(iii) Write the element which can shown an oxidation state of +1.

(iv) Which element is a strong oxidizing agent in +3 oxidation state and why?

Nuclear power station consists of nuclear reactor, in which a controlled chain reaction involving nuclear fission occurs using either U or Pu as fuel in reactor.The heat produced is extracted from the reactor and this heat is used to generate steam which drives a turbine and produces electricity.U or Pu can also be used in making atom bombs.The subcritical mass of U or Pu is carried out in aeroplanes and combine them to give a critical mass when dropped over the target. It leads to uncontrolled chain reaction which produces tremendous amount of energy and lot of destruction.Plutonium bomb was dropped over Hiroshima and Nagasaki, Japan in world War II which caused lot of destruction.
Answer the following questions.
(i) Should we use U and Pu for making atom bombs?
(ii) What is the long term disadvantages of nuclear radiation?
(iii) Why is U-235 used in nuclear reactor?
(iv) Why are breeder reactors more useful?