Chemical bonding basics — Identify the false statement about molecules held together predominantly by covalent bonds.
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AElectrons are shared between the atoms that make up the molecule
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BNoncovalent bonds may also be present, especially if the molecule is large
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CSuch molecules often result from the interaction of ionized atoms
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DThe chemical bonds that hold the molecule together are relatively strong
Answer
Correct Answer: Such molecules often result from the interaction of ionized atoms
Explanation
Introduction / Context:Chemical bonding includes covalent, ionic, hydrogen, and other noncovalent interactions. Distinguishing their defining features is foundational in biochemistry and materials science, because bond type dictates structure, stability, and reactivity.
Given Data / Assumptions:
- Covalent bonds arise from electron sharing between atoms (typically nonmetals).
- Large molecules can also contain noncovalent interactions (e.g., hydrogen bonds) stabilizing higher-order structure.
- We must spot the statement that mischaracterizes covalent molecules.
Concept / Approach:Ionic compounds result from electron transfer and electrostatic attraction of ions, whereas covalent molecules derive from shared electron pairs. Although atoms can be partially charged in polar covalent bonds, the molecules are not “formed from ionized atoms” in the ionic sense. Thus, calling covalent molecules products of ionized atom interactions is incorrect.
Step-by-Step Solution:
Evaluate each statement against standard definitions.Confirm shared electrons (true) and presence of ancillary noncovalent forces (true).Identify the false claim: formation from ionized atoms (ionic behavior) → not typical for covalent molecules.Recognize covalent bonds are relatively strong compared to noncovalent interactions (true).Verification / Alternative check:Textbook definitions clearly distinguish ionic (electron transfer) from covalent (electron sharing) bonding frameworks.
Why Other Options Are Wrong:
- Electron sharing: hallmark of covalency (correct).
- Noncovalent bonds present in large molecules: common for tertiary/quaternary structure (correct).
- Relatively strong bonds: covalent bond energies typically tens to hundreds of kJ/mol (correct).
Common Pitfalls:Confusing polar covalent partial charges with fully ionized species forming ionic lattices.
Final Answer:Such molecules often result from the interaction of ionized atoms