Metalloids
Metalloids have properties that are intermediate between metals and non-metals. They have properties that are difficult to characterize.
Physical Properties of Metalloids
State of matter - Solid
Lustre - Metallic lustre
Elasticity - Brittle
Conductivity - Semi-conductive in nature
Chemical Properties of Metalloids
Oxidation - They are capable of forming glasses.
Alloys - When mixed with metals, they form alloys.
Allotropic - Metallic and non-metallic allotropes are formed.
Melting - Few metalloids contract when they are melted.
Compounds - Compounds are formed when they react with halogens.
Common Properties of Metalloids
- Metalloids are good semiconductors.
- The reactivity of metalloids is dependent on the properties of the elements they are reacting with.
- Electronegativity and ionization energy are between metals and non-metals.
Non-Metals
Non-metals are those which lack all the metallic attributes. They are good insulators of heat and electricity. They are mostly gases and sometimes liquid. Some they are even solid at room temperatures like Carbon, sulphur and phosphorus.
Properties of Non metals
Characteristic properties of non-metals are high ionization energies and high electronegativity. Owing to these properties, non-metals usually gain electrons when reacting with other compounds, forming covalent bonds. Among the non-metals, the anionic dopants have a strong influence on the VB. Non-Metal dopants are carbon, nitrogen, fluorine, sulphur and iodine.
General properties of non-metals.
- The atoms of non-metals tend to be smaller than those of metals. Several of the other properties of non-metals result from their atomic sizes.
- Non-metals exhibit very low electrical conductivities. The low or non-existent electrical conductivity is the most important property that distinguishes non-metals from metals.
- Non-metals have high electronegativities. This means that the atoms of non-metals have a strong tendency to attract more electrons than what they would normally have.
- Non-metals have high electronegativities. This means that the atoms of non-metals have a strong tendency to hold on to the electrons that already have. In contrast, metals rather easily give up one or more electrons to non-metals, metal therefore easily form positively charged ions, and metals readily conduct electricity.
- Under normal conditions of temperature and pressure, some non-metals are found as gases, some found as solids and one is found as liquid. In contrast, except mercury, all metals are solids at room temperature. The fact that so many non-metals exist as liquids or gases means that non-metals generally have relatively low melting and boiling points under normal atmospheric conditions.
- In their solid-state, non-metals tend to be brittle. Therefore, they lack the malleability and ductility exhibited by metals.
Physical Properties of Non-Metals
- Ductility is the property of the material to be stretched into wires but non-metals are not ductile except for carbon, as carbon fibres find uses in a wide variety of industries including sports and music equipment.
- Another property characteristic to metals is absent in non-metals called malleability. They can’t be drawn into sheets as they are brittle and break on applying pressure.
- They are not lustrous as they do not have any shiny appearance.
- They are not sonorous and do not produce a deep ringing sound when they are hit with another material. They are also bad conductors of heat and electricity except for graphite.
