Which one of the following is not true for minerals? A) they can be a liquid, solid, or glass B) they have a specific, internal, crystalline structure C) they can be identified by characteristic physical properties D) they have a specific, predictable chemical composition
The Correct Answer and Explanation is :
Correct Answer:
A) They can be a liquid, solid, or glass
Explanation:
Minerals are naturally occurring, inorganic substances with a definite chemical composition and a crystalline structure. Let’s analyze why option A is incorrect and why the other options are true.
- Minerals must be solids
- A fundamental characteristic of minerals is that they exist as solids under normal Earth conditions. They cannot be liquids or gases.
- Liquids, such as water or mercury (which is a liquid metal), are not considered minerals because they lack a fixed crystalline structure.
- Glass is also not a mineral because it lacks a definite internal crystalline structure; it is an amorphous solid.
- Minerals have a specific, internal, crystalline structure (Option B – True)
- A mineral’s atoms are arranged in a specific, repeating pattern known as a crystalline structure.
- This structure gives minerals their unique shapes and properties, like cleavage and hardness.
- Minerals can be identified by characteristic physical properties (Option C – True)
- Each mineral has distinct physical properties, such as hardness, luster, color, streak, and cleavage, which help in identification.
- For example, quartz is hard and has a glassy luster, while pyrite (fool’s gold) has a metallic luster.
- Minerals have a specific, predictable chemical composition (Option D – True)
- Every mineral has a definite chemical composition, which can be either a single element (like gold, Au) or a compound (like quartz, SiO₂).
- The composition may have slight variations due to impurities, but the general formula remains predictable.
Conclusion:
Since minerals must be solid, option A is incorrect, making it the correct answer to the question.