MYP Chemistry Metals and Non-metals Notes

Metals and Non-Metals

1. Consider trying to bend a metal spoon and a piece of chalk.
2. The spoon flexes a little, but the chalk snaps in two.
3. These contrasting behaviours illustrate the fundamental differences between metals and non-metals, two broad categories of elements with distinct properties.
4. Most of the elements in the periodic table are metals.
5. Non-metals, although fewer in number, play crucial roles in areas such as biochemistry, materials science and electronics.

Physical Properties of Metals

Most metals share the following physical properties:

1. Shiny (lustrous):
   1. They reflect light.
   2. A polished silver spoon or a new aluminium can is a good example.
2. Good conductors of electricity and heat:
   1. Metals such as copper are used in electrical wiring because they allow electric current and heat to pass through them easily.
3. Malleable:
   1. They can be hammered or rolled into thin sheets without breaking.
   2. Aluminium foil is a familiar example of a very thin metal sheet.
4. Ductile:
   1. They can be stretched (drawn) into wires.
   2. Gold, for example, can be drawn into extremely thin wires.
5. High melting and boiling points:
   1. Most metals are solid at room temperature and melt only at high temperatures (the main exception you will meet is mercury, which is a liquid at room temperature).
6. High density:
   1. Many metals, such as iron and lead, feel heavy for their size.
7. Sonorous:
   1. They produce a ringing sound when struck (for example, a metal bell or a school gong).

Physical Properties of Non-Metals

In contrast, many non-metals show the opposite pattern of properties:

1. Dull:
   1. They usually lack the shine of metals.
   2. For example, solid sulfur and carbon (charcoal) appear dull.
2. Poor conductors:
   1. Most non-metals are insulators, meaning they do not conduct heat or electricity well.
   2. This makes them useful for covering wires (plastic) or insulating buildings (foam, fibreglass).
3. Brittle (when solid):
   1. Solid non-metals tend to break or shatter when hit, rather than bend.
4. Lower melting and boiling points:
   1. Many non-metals are gases at room temperature (for example oxygen and nitrogen), and several solid non-metals melt or boil at relatively low temperatures compared with metals.
5. Lower density: