List of top Chemistry Questions on d -and f -Block Elements

The oxidation state of Cr in $\text{K}_2\text{Cr}_2\text{O}_7$ is:
Which of the following statements is correct about Hg?
What is meant by lanthanoid contraction? (ii) Why do transition metals form coloured compounds? (iii) Why are $E^\circ_{M^{2+}/M}$ values for Mn and Zn more negative than expected? (iv) Which is the most stable oxidation state of Cu and why? (v) Why is Ce$^{4+}$ in aqueous solution a good oxidising agent?
(I) Why do transition metals show variable oxidation states? (II) Out of Mn$^{2+}$ and Ti$^{2+}$ which will be more paramagnetic and why? Atomic No.: Ti = 22, Mn = 25 (III) Which ion is the strongest oxidising agent in the options given below: \[ Cr^{3+},\ V^{3+},\ Mn^{3+} \] Atomic No.: Cr = 24, V = 23, Mn = 25 (ii) Complete and balance the following equations: (I) \[ 2MnO_2+4KOH+O_2\rightarrow ? \] (II) \[ 5C_2O_4^{2-}+2MnO_4^-+16H^+\rightarrow ? \]
Assertion (A) : Highest oxidation state of Mn is +7 in first series of transition elements. Reason (R) : Transition metals exhibit variable oxidation states.
Assertion (A): Separation of Zr and Hf is difficult. Reason (R): Because Zr and Hf lie in the same group of the periodic table.
In aqueous solution, \(Cr_2O_7^{2-}\) ion converts to which of the following in alkaline medium?
Given below are two statements Statement-I: Due to lanthanoid contraction 4d- and 5d-series of elements have more or less same atomic and ionic radii Statement-II: Lanthanoids exhibit more number of oxidation states than actinoids
513 K पर \(KMnO_4\) को गर्म करने पर बनने वाली हरी अनुचुम्बकीय प्रजाति (species) है :
चार अधूरित इलेक्ट्रॉनों वाला लैंथेनाइड आयन है (दिया है : \(Ce=58,\; Nd=60,\; Tb=65,\; Ho=67\) परमाणु क्रमांक)
Among the four complex ions given, identify the pair of ions with same spin only magnetic moment value:
An antibiotic which is bactericidal in nature is:
Given below are two statements: Statement-I: The oxidation state of phosphorus in the sodium salt of oxoacid formed when white phosphorus reacts with aqueous alkali solution is +1. Statement-II: Sulphur gives two gaseous products when treated with conc. \(HNO_3\).
Which of the following is most basic ?
Assertion (A): Actinoids show wide range of oxidation states.
Reason (R): Actinoids are radioactive in nature.
Which of the following is not a transition metal?
Match the atoms/ions given in Column-I with the number of unpaired electrons possessed by them as given in Column-II. \[ \begin{array}{llll} (a) & Cr & (p) & 1 \\[6pt] (b) & Mn^{2+} & (q) & 3 \\[6pt] (c) & N & (r) & 5 \\[6pt] (d) & Sc^{2+} & (s) & 6 \end{array} \]
Describe, giving the reason, which one of the following pairs has the property indicated :
(I) Fe or Cu – higher melting point
(II) $\mathrm{Ti^{3+}}$ or $\mathrm{Sc^{3+}}$ – coloured in aqueous solution
(III) Cr or Zn – higher third ionisation enthalpy
Assertion (A): Transition metals show their highest oxidation state with oxygen.
Reason (R): The ability of oxygen to form multiple bonds to metals.
Which of the following transition metals shows +1 and +2 oxidation states ?
Which of the following transition metals shows +1 and +2 oxidation states ?
Match the following orders with their properties.
At temperature \(T\) K, \(2\) moles of liquid \(A\) and \(3\) moles of liquid \(B\) are mixed. The vapour pressure of the ideal solution formed is \(320\) mm Hg. At this stage, one mole of \(A\) and one mole of \(B\) are added to the solution. The vapour pressure is now measured as \(328.6\) mm Hg. The vapour pressures (in mm Hg) of pure \(A\) and pure \(B\) respectively are:
This sulphide is not black:
From the given data of \(E^{\circ}\) values, answer the following questions :
(I) Why \(E^{\circ}_{M^{2+}/M}\) show irregular trend in the above values ?
(II) Why is \(E^{\circ}_{Cu^{2+}/Cu}\) value exceptionally positive ?
(III) Why \(E^{\circ}_{Mn^{2+}/Mn}\) value is highly negative ?