171.

The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition elements which shows highest magnetic moment?

• 3d⁷

• 3d⁸

• 3d⁵

• 3d²

Which of the following statement is wrong regarding lanthanoids?

• Ln(III) compounds are predominantly ionic in character.

• Ln(III) compound are generally colourless

• Ln(III) hydroxide are mainly basic in nature

• The ionic size of Ln(III) ions decreses with increasing atomic number.

For d block elements the first ionization potential is of the order :

• Zn > Fe > Cu > Cr

• Sc = Ti < V = Cr

• Zn < Cu < Ni < Co

• V > Cr > Mn > Fe

Fe²⁺ ion is distinguished from Fe³⁺ ion by :

• BaCl₂

• KCN

• NaNO₃

• NH₄SCN

Which of the following metal ions is not coloured?

• Ti³⁺

• Fe³⁺

• V²⁺

• Zn²⁺

The lanthanide contraction is responsible for the fact that

• Zr and Zn have the same oxidation state

• Zr and Hf have about the same radius

• Zr and Nb have similar oxidation state

• Zr and Y have about the same radius

The correct order of ionic radii of Y³⁺, La³⁺, Eu³⁺ and Lu³⁺ is

(Atomic no. Y = 39, La = 57, Eu = 63, Lu = 71)

• Lu³⁺ < Eu³⁺ < La³⁺ < Y³⁺

• La³⁺ < Eu³⁺ < Lu³⁺ < Y³⁺

• Y³⁺ < La³⁺ < Eu³⁺ < Lu³⁺

• Y³⁺  < Lu³⁺ < Eu³⁺ < La³⁺

Green vitriol is:

• FeSO₄·7H₂O

• ZnSO₄·7H₂O

• CuSO₄·5H₂O

• CuSO₄·1/2H₂O

When copper sulphate solution is added to potassium ferrocyanide, the formula of product obtained is

• Cu₂Fe(CN)₆

• Cu(CN)₃

• CuFe(CN)₆

• Cu(CN)₂

Formation of coloured ions by transition metals signifies;

• absorption of light from UV range

• emission of light

• presence of unparied electrons in s and p orbitals

• complimentary colours to the absorbed light