A solid melts sharply just above 100 degree centigrade. It does not conduct electricity even when molten. It has weak Vander waal's forces. What is the structure of the solid most likely to be?
Correct answer: C. a molecular crystal
- A. An atomic crystal
- B. ionic crystal
- C. a molecular crystal
- D. metallic
Explanation
The structure mentioned above is a molecular crystal because molecular crystals have low melting points as the one mentioned above, have weak intermolecular forces like Vander waal forces and can not conduct electricity due to unavailability of free moving charge. Ionic crystals can not be the answer because it has a lot higher melting point, same goes for metallic crystals and atomic crystals which are not held by weak forces but much stronger forces. Atomic crystals, in fact, have strong covalent bonds that hold them together.
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About Ionic and Molecular Crystals
Ionic crystals contain oppositely charged ions held by electrostatic forces, whereas molecular crystals contain discrete molecules joined by weaker intermolecular forces. Their structures explain differences in melting point, hardness, volatility, solubility and electrical conductivity, especially between solid and molten states.
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