d and f Block Elements

The transition series that includes the element Platinum ($Pt$) is the:

The valence shell electronic configuration of Group 3 elements like Scandium is generally represented as:

Which of the following elements is a liquid at room temperature and belongs to the $d$-block?

What is the number of $d$-electrons in $Fe^{3+}$ ($Z = 26$)?

Ruthenium ($Z = 44$) is an element in the $4d$ transition series that exhibits an anomalous ground state electronic configuration due to the relative energies of its orbitals. Based on the classification of transition series elements shown in the diagram, which of the following represents the correct ground state electronic configuration of Ruthenium?

Which of the following $d$-block elements has the maximum number of stable oxidation states?

Electronic configuration of $Hf$ ($Z=72$) is:

Why is the density of $5d$ series elements much higher than that of $4d$ series elements?

Which of the following $3d$ ions is expected to have a magnetic moment of $0 \text{ BM}$?

The electronic configuration $[Xe] 4f^1 5d^1 6s^2$ corresponds to which lanthanoid?

Transition metals like Iron ($Fe$, $Z=26$) exhibit variable oxidation states by losing electrons from their outer $4s$ and inner $3d$ subshells. Based on the electron loss sequence provided in the flowchart, which of the following pairs represents the most common oxidation states of Iron?

Which of the following alloys contains a transition metal and a non-metal?

Lanthanoid contraction is caused by:

Which of the following is a paramagnetic ion?

Although Fluorine is more electronegative than Oxygen, the highest oxidation state of Manganese is observed in its oxide ($MnO_4^-$) where it is $+7$, whereas in its fluoride ($MnF_4$), it is only $+4$. Based on the bonding characteristics represented in the diagram, what is the primary reason for this difference?

The color of transition metal ions is attributed to the excitation of an electron from a lower energy $d$-orbital to a higher energy $d$-orbital. Based on the Crystal Field splitting diagram shown below for an octahedral field, which of the following ions is colorless because it possesses a $d^0$ electronic configuration?

Which lanthanoid element is obtained by synthetic means (not found in nature)?

The deviation of $Eu^{3+}$ ($4f^6$) and $Sm^{3+}$ ($4f^5$) from the theoretical magnetic moment calculated by the Landé formula at $298\,K$ is a significant anomaly in lanthanoid chemistry. This deviation occurs because:

Potassium hexachloroplatinate ($K_2PtCl_6$) is a stable compound, whereas the corresponding nickel compound $K_2NiCl_6$ is not known to exist under ordinary conditions. This marked difference in the stability of the $+4$ oxidation state between Nickel and Platinum is primarily attributed to which thermodynamic factor?

The acidic character of the oxides of a particular transition metal follows which trend?

Which of the following $M^{2+}$ ions has the smallest radius in the first transition series?

Which of the following $5d$ elements has an atomic radius very similar to Rhenium ($Re$)?

What is the trend in atomic radius from $Sc$ to $Y$ to $La$?

Which element in the $3d$ series has an atomic radius most similar to that of $Mn$?

Which of the following factors contributes to the Actinoid contraction more than to the Lanthanoid contraction?

What happens to the atomic radii of $d$-block elements when moving down from the second ($4d$) to the third ($5d$) transition series?

In the $3d$ series, the decrease in atomic radius is most significant between:

Which of the following is a result of the d-block contraction occurring after the $3d$ series is filled?

Considering the Lanthanoid series, which of the following properties shows a decrease as the ionic radius decreases?

In the $3d$ series, $Ti^{2+}$ has a radius of $86\,pm$ and $V^{2+}$ has $79\,pm$. This decrease is due to:

Which oxidation state of Manganese is the most stable in acidic aqueous solution?

Among the $3d$ series, which element's $IE_2$ is unexpectedly low because it leads to a $d^{10}$ configuration?

What is the common oxidation state of Silver ($Ag$) in its compounds?

The element $Lu$ ($Z=71$) shows only $+3$ oxidation state because:

Which of the following $3d$ transition metal ions has the highest $IE_4$?

The ionic radius of $M^{2+}$ ions decreases across the $3d$ series. How does this affect the ionization enthalpy?

Why is the $+6$ oxidation state of Chromium in $K_2Cr_2O_7$ a strong oxidizing agent, while the $+6$ state of Tungsten in $WO_3$ is stable?

What is the primary reason that $Eu^{2+}$ is a strong reducing agent while $Ce^{4+}$ is a strong oxidizing agent?

Which of the following ions is paramagnetic and has the highest stable oxidation state in its respective series?

The ionization enthalpy of the 5d elements is higher than 4d. This trend is a deviation from the usual group trend. Which other property shows a similar anomalous trend due to the same reason?

What is the magnetic moment of $Zn^{2+}$ ion ($Z=30$)?

In the lead chamber process, which of the following acts as a catalyst?

Which of the following is paramagnetic?

Magnetic moment of $V^{4+}$ is same as that of:

What is the magnetic moment of $Mn^{3+}$ ($Z=25$)?

Identify the incorrect statement regarding transition metal catalysts.

A $3d$ transition metal ion $M^{x+}$ has a magnetic moment of $2.83$ BM. If its atomic number is $28$, what is the value of $x$?

In the $3d$ transition series, the magnetic moment of ions typically corresponds to the 'spin-only' value because the orbital angular momentum is 'quenched' by the surrounding ligand field. In contrast, for the lanthanide series ($4f$), the magnetic moment is determined by the total angular momentum quantum number $J$ because the orbital contribution is preserved. Which of the following provides the correct structural explanation for why the orbital angular momentum is NOT quenched in lanthanides?

Why is $Fe^{3+}$ a better catalyst than $Fe^{2+}$ in many oxidation-reduction reactions involving peroxide?

Calculate the magnetic moment of $Pr^{3+}$ ($4f^2$) using the spin-only formula and identify the discrepancy with its actual magnetic moment ($\\approx 3.58$ BM).

Which compound is formed when $CrO_{2}Cl_{2}$ is dissolved in $NaOH$ solution?

What is the equivalent mass of $KMnO_{4}$ when it is reduced to $K_{2}MnO_{4}$ in a strongly basic medium?

Which of the following is used to remove the yellow color of iron(III) during the preparation of $K_{2}Cr_{2}O_{7}$ from chromite?

In the alkaline oxidation of thiosulfate ($S_{2}O_{3}^{2-}$) by $KMnO_{4}$, the sulfur is oxidized to:

What is the change in the oxidation state of Manganese when $KMnO_{4}$ reacts with $SO_{2}$ in an acidic medium?

Which of the following properties is shared by both $CrO_{4}^{2-}$ and $MnO_{4}^{-}$?

What is the equivalent weight of $KMnO_{4}$ ($M$) in a strongly alkaline reaction where it is reduced to $K_{2}MnO_{4}$?

How many oxygen atoms are shared between the two tetrahedra in $Cr_{2}O_{7}^{2-}$?

In the reaction $2KMnO_{4} + 3H_{2}SO_{4} + 5H_{2}S \rightarrow K_{2}SO_{4} + 2MnSO_{4} + 8H_{2}O + 5S$, the n-factor of $H_{2}S$ is:

Which statement is true about the structure of $KMnO_{4}$?

The solubility of lanthanoid hydroxides in water is generally:

Which of the following lanthanoids has the smallest ionic radius in the +3 state?

Actinoids are called inner transition elements because they involve the filling of:

Which of the following is an example of a lanthanoid metal used in magnesium-based alloys for jet engines?

The term 'inner-transition elements' is applied to $f$-block elements because:

Lanthanoid hydroxides $Ln(OH)_3$ react with $CO_2$ to form:

Which element in the actinoid series has the electronic configuration $[Rn] 5f^0 6d^2 7s^2$?

Which of the following statements about the densities of lanthanoids is true?

The chemical behavior of 'early' actinoids (up to $Am$) is more similar to transition metals than 'late' actinoids. This is because:

Which actinoid is used as a fuel in nuclear reactors in the form of its oxide mixed with $UO_2$ (MOX fuel)?

Which element is the first member of the lanthanide series?

The melting points of lanthanides generally increase across the series. This is primarily because of:

Which oxidation state is shown by Europium ($Eu$) due to the stability of a half-filled $f$ subshell?

The ionic radius of $Y^{3+}$ is very close to which of the following lanthanoid ions?

The Lanthanoid contraction is fundamentally caused by the 'poor shielding' of the nuclear charge by $4f$ electrons. Hypothetically, if the shielding provided by each $4f$ electron were 'perfect' (where the increase in the shielding constant exactly matches the increase in atomic number), how would the atomic radii of the Lanthanoids most likely behave as the atomic number increases from $Ce$ to $Lu$?

What effect does Lanthanoid contraction have on the standard electrode potential of $Hf$ compared to $Zr$?

In the series of Lanthanoid tripositive ions ($Ln^{3+}$), which ion has the highest polarizing power?

The melting points of the lanthanoid metals generally increase from $La$ to $Lu$ (with exceptions for $Eu$ and $Yb$). This trend is primarily due to:

The 'Shielding Constant' ($\sigma$) for $4f$ electrons in lanthanoids increases as the atomic number increases. Why doesn't this negate the contraction?

In the series $La^{3+} \dots Lu^{3+}$, the ionic radius $r$ and atomic number $Z$ are related such that: