d and f BLOCK ELEMENTS MCQ Quiz: GKFix - Bridge of Knowledge

Question 21

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Why do the first ionization enthalpies of transition metals generally increase slightly across the series but show smaller variations compared to main group elements?

Because transition metals are metals.
Because the atomic size decreases.
Because the nuclear charge decreases.
Because the increasing nuclear charge is partially offset by the imperfect shielding provided by the filling d-electrons, and the ns electrons are removed first.

Question 22

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Why is the second ionization enthalpy of Chromium (Cr) lower than that of Vanadium (V), despite Cr having a higher atomic number?

Because Cr is a metal.
Because Cr has a higher atomic number.
Because removing the first electron from Cr (4s^1) leaves it closer to the stable d^5 configuration than removing the first electron from V (4s^2) which moves it away from d^5.
Because V has fewer electrons.

Question 23

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Why do the atomic radii of the second and third transition series elements not increase as much as expected compared to the first series?

Because they are heavier.
Because the nuclear charge increases.
Because the Lanthanoid contraction significantly reduces the expected increase in size when moving from the second to the third series.
Because the third series elements are less reactive.

Question 24

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Why do the melting points of transition metals generally peak around the middle of the series (e.g., Vanadium, Chromium, Manganese)?

Because they are transition metals.
Because the atomic size decreases.
Because metals in the middle of the series typically have the optimal number of unpaired d-electrons contributing to strong metallic bonding, balancing bond strength and electron delocalization.
Because they have high densities.

Question 25

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Why is the third ionization enthalpy of Vanadium (V) lower than that of Titanium (Ti), even though V has a higher atomic number?

Because V is a metal.
Because Ti has fewer electrons.
Because removing the third electron from V^2+ (d^3) does not disrupt a particularly stable configuration, whereas removing the third electron from Ti^2+ (d^2) disrupts the approach towards a more stable d^3 configuration less favorably.
Because V has a higher atomic number.

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