p-Block Elements: Groups 13-18 Flashcards for NEET — 20 cards

First 8 of 20 p-Block Elements: Groups 13-18 flashcards

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1. Card 1 of 20

   What is the general outer electronic configuration for p-block elements?

   Hint: Remember the valence shell fills the p-orbitals.

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   Answer

   The general outer electronic configuration is $ns^2 np^{1-6}$ (except for Helium which is $1s^2$).

2. Card 2 of 20

   List the three main reasons for the anomalous behavior of the first element in each p-block group.

   Hint: Why does Nitrogen act differently than Phosphorus?

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   Answer

   1. Smallest atomic size in the group. 2. Highest electronegativity and ionization enthalpy in the group. 3. Absence of vacant d-orbitals in its valence shell.

3. Card 3 of 20

   How does the absence of d-orbitals restrict the covalency of the first element in p-block groups?

   Hint: Boron forms [BF4]-, but Aluminum forms [AlF6]3-.

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   Answer

   The first element (belonging to the 2nd period) can only use one 2s and three 2p orbitals for bonding, restricting its maximum covalency to 4. Heavier elements can expand their octet using empty d-orbitals (covalency > 4).

4. Card 4 of 20

   Compare the ability to form pπ-pπ multiple bonds between the 1st element (like C, N, O) and heavier elements (like Si, P, S).

   Hint: Why is Nitrogen a diatomic gas (N2) but Phosphorus is a solid solid (P4)?

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   Answer

   The 1st elements readily form strong pπ-pπ multiple bonds (e.g., C=C, N≡N, C=O) because their p-orbitals are small and overlap effectively. Heavier elements have large, diffuse p-orbitals, making pπ-pπ overlap weak and ineffective.

5. Card 5 of 20

   What is the trend in atomic radius in Group 13 (Boron family)? Mention the specific anomaly.

   Hint: d-block contraction effect.

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   Answer

   Generally increases down the group, but there is an anomaly: Gallium (135 pm) is smaller than Aluminum (143 pm). Reason: Poor shielding by the completely filled 3d orbitals in Gallium increases the effective nuclear charge, pulling electrons closer.

6. Card 6 of 20

   Arrange the Group 13 elements (B, Al, Ga, In, Tl) in increasing order of stability of the +1 oxidation state.

   Hint: For Thallium (Tl), +1 is much more stable than +3.

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   Answer

   B < Al < Ga < In < Tl (The +1 state becomes increasingly stable down the group due to the Inert Pair Effect).

7. Card 7 of 20

   What is Catenation? Describe its trend down Group 14 (Carbon family).

   Hint: Carbon is the king of catenation.

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   Answer

   Catenation is the ability of like atoms to link together via covalent bonds to form long chains or rings. Trend decreases down the group as bond strength decreases: C >> Si > Ge ≈ Sn >> Pb (Pb does not show catenation).

8. Card 8 of 20

   Why is the boiling point of Ammonia (NH₃) unusually high compared to PH₃, but follows a regular trend after that (NH₃ > AsH₃ > PH₃... wait, what is the exact order)?

   Hint: Hydrogen bonding disrupts the normal 'molecular mass' trend.

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   Answer