Matter Around Us. — Science STD 8 — Question

Physical p roperties of non – metals:

1. Physical state:
Non – metals occur as solids, liquids or gases at normal temperature; for example sulphur, phosphorus occurs in solid state while bromine occurs in liquid state. Gases like oxygen, nitrogen, etc., occur in the gaseous state

2. Hardness:
Non – metals are generally not hard except diamond, (a form of carbon)
3. Lustre:
Non – metals have a dull appearance; Graphite and iodine are exceptions as they are shiny and lustrous.
4. Density:
Non – Metals are generally soft and have low densities. The exception here is diamond (a form of carbon) which’is the hardest naturally occurring substance
5. Melting point and boiling point:
Non – metals have low melting point and boiling point. However, carbon, silicon and boron are exceptions.
6. Tensile strength:
Non – metals do not have tensile strength. However, carbon fibre (a form of carbon) is as tensile as steel.
7. Malleability:
Non – metals are non-malleable. If hammered, they form a powdery mass. Actually non – metals in solid state are brittle in nature.
8. Ductility:
Non – metals are not ductile. Carbon fibre is highly ductile.
9. Conductivity:
Non – Metals are generally bad conductor of electricity. Graphite (a form of carbon) is exception.
10. Sonorous:
Non – metals do not produce sound (non – sonorous) when hit.