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Physical Properties of Non Metals Video Lecture | Science for Grade 6

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FAQs on Physical Properties of Non Metals Video Lecture - Science for Grade 6

1. What are the physical properties of non-metals?
Ans. Non-metals have several physical properties: - Non-metals are generally poor conductors of heat and electricity. - They have low melting and boiling points compared to metals. - Non-metals are usually brittle and cannot be rolled into wires or beaten into sheets. - They are often dull and lack luster. - Non-metals are mostly found in the gaseous or solid state at room temperature, with a few exceptions like bromine.
2. Why are non-metals poor conductors of heat and electricity?
Ans. Non-metals are poor conductors of heat and electricity because they do not have free electrons or delocalized electrons that can move freely within their atomic structure. In non-metals, the valence electrons are tightly bound to the nucleus, making it difficult for them to move and carry heat or electricity. This lack of free electrons results in non-metals having high electrical resistance and low thermal conductivity.
3. Why do non-metals have low melting and boiling points compared to metals?
Ans. Non-metals have low melting and boiling points compared to metals because the forces of attraction between their atoms or molecules are relatively weak. In non-metals, the atoms or molecules are held together by covalent bonds, which are formed by the sharing of electrons. These covalent bonds are weaker than the metallic bonds found in metals, where electrons are delocalized and shared among a sea of atoms. As a result, less energy is required to break the weaker covalent bonds in non-metals, leading to lower melting and boiling points.
4. Why are non-metals often brittle and cannot be rolled into wires or beaten into sheets?
Ans. Non-metals are often brittle and cannot be rolled into wires or beaten into sheets because their atomic or molecular structures lack the ability to deform plastically. In non-metals, the atoms or molecules are held together by strong covalent bonds, which require a significant amount of force to break. When subjected to external stress or pressure, the covalent bonds in non-metals tend to break, leading to the material fracturing or shattering rather than undergoing plastic deformation like metals. This brittleness makes non-metals unsuitable for applications requiring malleability and ductility.
5. Why are non-metals mostly found in the gaseous or solid state at room temperature?
Ans. Non-metals are mostly found in the gaseous or solid state at room temperature because their boiling points are generally lower than their melting points. At room temperature, some non-metals, such as oxygen, nitrogen, and chlorine, exist as gases due to their low boiling points. Others, like carbon, sulfur, and phosphorus, are solid non-metals at room temperature because their melting points are higher. The relatively weak forces of attraction between non-metal atoms or molecules contribute to their varied states at room temperature.
101 videos|191 docs|46 tests
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