What are the names of all the classes of substances that conduct electricity?
conductors.
If air resistance is neglible, the total mechanical energy of a free-falling body will be
A remains constant
B becomes zero
C increases
D decreases
To determine the names of all classes of substances that conduct electricity, we can start by understanding that the ability of a substance to conduct electricity is primarily influenced by the presence of charged particles, such as ions or free electrons, which can move and carry an electric current.
Here are four main classes of substances that can conduct electricity:
1. Metals: Metals are excellent conductors of electricity due to the presence of delocalized electrons. These electrons are loosely bound to the atoms and can move freely throughout the metallic structure, allowing for the flow of electric current.
2. Ionic Compounds: Ionic compounds are made up of positively charged ions (cations) and negatively charged ions (anions) held together by ionic bonds. In their molten state or when dissolved in water, these compounds become conductive as the ions are free to move and carry electric charge.
3. Aqueous Solutions: Many substances, when dissolved in water, dissociate into ions, forming aqueous solutions. These solutions can conduct electricity as the dissociated ions are able to move and conduct electric current.
4. Graphite: Graphite is a form of carbon that has a unique structure where carbon atoms are arranged in layers. Within these layers, the carbon atoms are strongly bonded, but the layers themselves are only weakly bonded, allowing for the movement of electrons in the plane of the layers. This property makes graphite a good conductor of electricity.
It's important to note that while these classes of substances are generally conductive, not all substances within each class are equally conductive. Certain factors, such as temperature, impurities, and concentration, can affect the conductivity of a given substance.