Chemistry Worksheets Class 11 on Chapter 4 Chemical Bonding and Molecular Structure - Set 1.
Chemistry Worksheets Class 11 on Chapter 4 Chemical Bonding and Molecular Structure - Set 1, featuring questions on hybridization, bond formation, and Lewis dot symbols.
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Step-by-step solution for: Class 11 Chemistry Worksheet on Chapter 4 Chemical Bonding and ...
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Show Answer Key & Explanations
Step-by-step solution for: Class 11 Chemistry Worksheet on Chapter 4 Chemical Bonding and ...
Here are the solutions to the chemistry worksheet questions.
Q-1: Which of the following carbon is more electronegative?
* Reasoning: Electronegativity depends on how close the shared electrons are to the nucleus. In hybrid orbitals, "s" character holds electrons closer to the nucleus than "p" character because s-orbitals are spherical and penetrate closer to the nucleus.
* $sp$ hybridization has 50% s-character.
* $sp^2$ hybridization has 33.3% s-character.
* $sp^3$ hybridization has 25% s-character.
* Since $sp$ has the highest percentage of s-character, it holds electrons most tightly and is the most electronegative.
* Answer: a) sp hybridised carbon
Q-2: In the ClF₃ molecule, the lone pairs occupy an equatorial position to minimise...
* Reasoning: According to VSEPR theory, electron repulsion follows this order: Lone Pair-Lone Pair (lp-lp) > Lone Pair-Bond Pair (lp-bp) > Bond Pair-Bond Pair (bp-bp). To make the molecule stable, we must minimize the strongest repulsions first. Placing lone pairs in the equatorial positions (120° apart) rather than axial positions (90° apart) reduces the number of strong 90° interactions between lone pairs and bond pairs. Therefore, the goal is to minimize both lp-lp and lp-bp repulsions.
* Answer: c) Lone pair - lone pair repulsion and lone pair - bond pair repulsion
Q-3: Which of the following statements is false?
* Reasoning: Let's check each statement:
* a) Covalent radius is defined as half the distance between nuclei of two identical atoms bonded together. So, double the radius is the distance. This is True.
* b) Van der Waals radius is defined as half the distance between nuclei of two non-bonded atoms of adjacent molecules. This is True.
* c) X-ray diffraction, electron diffraction, and spectroscopy are standard scientific methods used to determine bond lengths. This is True.
* d) Since all statements above are true, "None of the above" is the correct choice for "which is false".
* Answer: d) None of the above
Q-4: A $\pi$-bond is formed by the overlap of...
* Reasoning:
* Sigma ($\sigma$) bonds are formed by head-on (end-to-end) overlap.
* Pi ($\pi$) bonds are formed by the lateral (sidewise) overlap of atomic orbitals. This usually happens between parallel p-orbitals.
* Answer: d) p-p orbitals in a sidewise manner
Q-5: Which of the following accurately describes the prerequisites for the formation of an electrovalent bond?
* Reasoning: An electrovalent (ionic) bond forms when one atom gives up an electron (becoming a cation) and another accepts it (becoming an anion).
* The atom giving the electron needs low ionisation potential (easy to remove an electron).
* The atom accepting the electron needs high electron affinity (strong desire to gain an electron).
* Answer: a) Low ionisation potential of one atom and high electron affinity of the other atom.
Q-6: What is the valence bond approach for forming a covalent bond and a coordinate bond?
* Reasoning:
* Covalent Bond: Formed by the mutual sharing of one electron from each participating atom. The orbitals overlap, and the electron spins must be opposite (paired).
* Coordinate Bond (Dative): A special type of covalent bond where the shared pair of electrons is donated by only one atom (the donor) and accepted by the other (the acceptor).
Q-7: Write Lewis dot symbols for the following ions: i) O²⁻
* Reasoning:
* Oxygen (O) is in Group 16 and has 6 valence electrons.
* The ion O²⁻ has gained 2 electrons to complete its octet.
* Total valence electrons = $6 + 2 = 8$.
* The symbol is written with 8 dots around the letter O, enclosed in brackets with the charge outside.
──────────────────────────────────────
Final Answer:
Q-1: a) sp hybridised carbon
Q-2: c) Lone pair - lone pair repulsion and lone pair - bond pair repulsion
Q-3: d) None of the above
Q-4: d) p-p orbitals in a sidewise manner
Q-5: a) Low ionisation potential of one atom and high electron affinity of the other atom.
Q-6: A covalent bond is formed by the mutual sharing of electron pairs between atoms. A coordinate bond is formed when one atom provides both electrons for the shared pair.
Q-7: [ :Ö : ]²⁻ (An Oxygen symbol surrounded by 8 dots, inside brackets with a 2- charge)
Q-1: Which of the following carbon is more electronegative?
* Reasoning: Electronegativity depends on how close the shared electrons are to the nucleus. In hybrid orbitals, "s" character holds electrons closer to the nucleus than "p" character because s-orbitals are spherical and penetrate closer to the nucleus.
* $sp$ hybridization has 50% s-character.
* $sp^2$ hybridization has 33.3% s-character.
* $sp^3$ hybridization has 25% s-character.
* Since $sp$ has the highest percentage of s-character, it holds electrons most tightly and is the most electronegative.
* Answer: a) sp hybridised carbon
Q-2: In the ClF₃ molecule, the lone pairs occupy an equatorial position to minimise...
* Reasoning: According to VSEPR theory, electron repulsion follows this order: Lone Pair-Lone Pair (lp-lp) > Lone Pair-Bond Pair (lp-bp) > Bond Pair-Bond Pair (bp-bp). To make the molecule stable, we must minimize the strongest repulsions first. Placing lone pairs in the equatorial positions (120° apart) rather than axial positions (90° apart) reduces the number of strong 90° interactions between lone pairs and bond pairs. Therefore, the goal is to minimize both lp-lp and lp-bp repulsions.
* Answer: c) Lone pair - lone pair repulsion and lone pair - bond pair repulsion
Q-3: Which of the following statements is false?
* Reasoning: Let's check each statement:
* a) Covalent radius is defined as half the distance between nuclei of two identical atoms bonded together. So, double the radius is the distance. This is True.
* b) Van der Waals radius is defined as half the distance between nuclei of two non-bonded atoms of adjacent molecules. This is True.
* c) X-ray diffraction, electron diffraction, and spectroscopy are standard scientific methods used to determine bond lengths. This is True.
* d) Since all statements above are true, "None of the above" is the correct choice for "which is false".
* Answer: d) None of the above
Q-4: A $\pi$-bond is formed by the overlap of...
* Reasoning:
* Sigma ($\sigma$) bonds are formed by head-on (end-to-end) overlap.
* Pi ($\pi$) bonds are formed by the lateral (sidewise) overlap of atomic orbitals. This usually happens between parallel p-orbitals.
* Answer: d) p-p orbitals in a sidewise manner
Q-5: Which of the following accurately describes the prerequisites for the formation of an electrovalent bond?
* Reasoning: An electrovalent (ionic) bond forms when one atom gives up an electron (becoming a cation) and another accepts it (becoming an anion).
* The atom giving the electron needs low ionisation potential (easy to remove an electron).
* The atom accepting the electron needs high electron affinity (strong desire to gain an electron).
* Answer: a) Low ionisation potential of one atom and high electron affinity of the other atom.
Q-6: What is the valence bond approach for forming a covalent bond and a coordinate bond?
* Reasoning:
* Covalent Bond: Formed by the mutual sharing of one electron from each participating atom. The orbitals overlap, and the electron spins must be opposite (paired).
* Coordinate Bond (Dative): A special type of covalent bond where the shared pair of electrons is donated by only one atom (the donor) and accepted by the other (the acceptor).
Q-7: Write Lewis dot symbols for the following ions: i) O²⁻
* Reasoning:
* Oxygen (O) is in Group 16 and has 6 valence electrons.
* The ion O²⁻ has gained 2 electrons to complete its octet.
* Total valence electrons = $6 + 2 = 8$.
* The symbol is written with 8 dots around the letter O, enclosed in brackets with the charge outside.
──────────────────────────────────────
Final Answer:
Q-1: a) sp hybridised carbon
Q-2: c) Lone pair - lone pair repulsion and lone pair - bond pair repulsion
Q-3: d) None of the above
Q-4: d) p-p orbitals in a sidewise manner
Q-5: a) Low ionisation potential of one atom and high electron affinity of the other atom.
Q-6: A covalent bond is formed by the mutual sharing of electron pairs between atoms. A coordinate bond is formed when one atom provides both electrons for the shared pair.
Q-7: [ :Ö : ]²⁻ (An Oxygen symbol surrounded by 8 dots, inside brackets with a 2- charge)
Parent Tip: Review the logic above to help your child master the concept of molecular structure worksheet.
