Identify the incorrect statement.

Read the following passage and answer the next five questions based on it:

Sc	Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn
Y	Zr	Nb	Mo	Te	Ru	Rh	Pd	Ag	Cd
La	Hf	Ta	W	Re	Os	Ir	Pt	Au	Hg

In any transition series, as we move from left to right the $d-$orbitals are progressively filled and their properties vary accordingly

The above are the two series of f-block elements in which the chemical properties won't change much. The 5f-series elements are radioactive in nature and mostly are artificially synthesized in laboratories and thus much is not known about their chemical properties.

Identify the incorrect statement.

Answer & explanation

Correct answer: option 2

The correct answer is option (2) -Zr and Hf shares almost identical nuclear properties.

Statement-wise Evaluation

Option 1. Second ionization enthalpy of Ag is greater than second ionization enthalpy of Pd : Correct

Ag configuration: $[\text{Kr}] \, 4d^{10} 5s^1$

$1^{\text{st}}$ IE removes $5s^1 \rightarrow \text{Ag}^+$ becomes $4d^{10}$ (very stable)
$2^{\text{nd}}$ IE removes an electron from filled $4d^{10}$ shell $\rightarrow$ requires very high energy

Pd configuration: $[\text{Kr}] \, 4d^{10} 5s^0$

Removing two electrons does not involve breaking an already formed $\text{Ag}^+$-type extra stability.

Therefore, second ionization enthalpy of $\text{Ag}$ is indeed higher than $\text{Pd}$.

So Statement 1 is true.

2. Zr and Hf share almost identical nuclear properties: Incorrect statement

$\text{Zr}$ and $\text{Hf}$ are similar due to lanthanide contraction, which affects atomic size and chemical/physical properties.
Nuclear properties relate to isotopes, binding energy, radioactivity, etc. — these are not identical.
Textbooks always say chemical properties, not nuclear.

Hence this statement is factually wrong.

3. Melting point of Mn is lower than that of Cr : Correct

$\text{Mn}$ has relatively weaker metallic bonding compared to $\text{Cr}$, so its melting point is lower. This is a known irregular trend in the $3d$ series.

4. Interstitial compounds are non-stoichiometric and neither ionic nor covalent: Correct

They are metallic in character and usually non-stoichiometric. This is standard theory of transition metals.

Read the following passage and answer the next five questions based on it:

Sc	Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn
Y	Zr	Nb	Mo	Te	Ru	Rh	Pd	Ag	Cd
La	Hf	Ta	W	Re	Os	Ir	Pt	Au	Hg

In any transition series, as we move from left to right the $d-$orbitals are progressively filled and their properties vary accordingly

Identify the incorrect statement.

Answer & explanation

Correct answer: option 2

The correct answer is option (2) -Zr and Hf shares almost identical nuclear properties.

Statement-wise Evaluation

Option 1. Second ionization enthalpy of Ag is greater than second ionization enthalpy of Pd : Correct

Ag configuration: $[\text{Kr}] \, 4d^{10} 5s^1$

$1^{\text{st}}$ IE removes $5s^1 \rightarrow \text{Ag}^+$ becomes $4d^{10}$ (very stable)
$2^{\text{nd}}$ IE removes an electron from filled $4d^{10}$ shell $\rightarrow$ requires very high energy

Pd configuration: $[\text{Kr}] \, 4d^{10} 5s^0$

Removing two electrons does not involve breaking an already formed $\text{Ag}^+$-type extra stability.

Therefore, second ionization enthalpy of $\text{Ag}$ is indeed higher than $\text{Pd}$.

So Statement 1 is true.

2. Zr and Hf share almost identical nuclear properties: Incorrect statement

$\text{Zr}$ and $\text{Hf}$ are similar due to lanthanide contraction, which affects atomic size and chemical/physical properties.
Nuclear properties relate to isotopes, binding energy, radioactivity, etc. — these are not identical.
Textbooks always say chemical properties, not nuclear.

Hence this statement is factually wrong.

3. Melting point of Mn is lower than that of Cr : Correct

$\text{Mn}$ has relatively weaker metallic bonding compared to $\text{Cr}$, so its melting point is lower. This is a known irregular trend in the $3d$ series.

4. Interstitial compounds are non-stoichiometric and neither ionic nor covalent: Correct

They are metallic in character and usually non-stoichiometric. This is standard theory of transition metals.