Chemical Bonding & Molecular Structure Flashcards for NEET — 20 cards

First 8 of 20 Chemical Bonding & Molecular Structure flashcards

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1. Card 1 of 20

   What is the VSEPR shape of a molecule with 2 bond pairs and 2 lone pairs (e.g., $H_2O$)?

   Hint: The basic geometry is tetrahedral, but the lone pairs push the bonds closer together.

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   Answer

   Bent or V-shaped.

2. Card 2 of 20

   What is the formula for calculating the Formal Charge on an atom in a Lewis structure?

   Hint: Valence - Dots - Lines

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   Answer

   Formal Charge = [Total Valence Electrons] - [Non-bonding Electrons] - 1/2 [Bonding Electrons]

3. Card 3 of 20

   Give two examples of molecules that violate the Octet Rule by having an 'Expanded Octet'.

   Hint: Elements in period 3 or higher can expand their octet using empty d-orbitals.

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   Answer

   $PF_5$ (10 valence electrons around P), $SF_6$ (12 valence e-), or $H_2SO_4$.

4. Card 4 of 20

   According to Fajan's Rule, what conditions favor high covalent character in an ionic bond?

   Hint: Higher polarizing power of cation + higher polarizability of anion.

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   Answer

   1. Small size of cation. 2. Large size of anion. 3. High charge on either ion.

5. Card 5 of 20

   What two main factors favor the formation of ionic bonds with high Lattice Enthalpy?

   Hint: Coulomb's Law: Force is proportional to $q_1 q_2 / r^2$

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   Answer

   High charge on the ions and small size of the ions.

6. Card 6 of 20

   Why does $BF_3$ have a net dipole moment of zero despite having polar B-F bonds?

   Hint: Symmetry kills polarity.

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   Answer

7. Card 7 of 20

   What is the VSEPR shape of a molecule with 4 bond pairs and 1 lone pair (e.g., $SF_4$)?

   Hint: Derived from trigonal bipyramidal geometry ($sp^3d$ hybridization) where the lone pair occupies an equatorial position.

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   Answer

   See-saw shape.

8. Card 8 of 20

   What is the shape and hybridization of the $XeF_4$ molecule?

   Hint: 4 bond pairs + 2 lone pairs. Lone pairs sit axially opposite each other to minimize repulsion.

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   Answer

   Square planar shape, $sp^3d^2$ hybridization.