How can electrical conductivity be used to determine bond type?
(In your CER make sure to also explain why different bonds behave differently)
1 claim 3 reasoning and 3 evidence
Claim: Electrical conductivity can be used to determine bond type because different bonds behave differently based on their ability to conduct electricity.
Reasoning:
1. Ionic bonds: Ionic bonds involve the transfer of electrons from one atom to another. In ionic compounds, the positive and negative ions are held together by electrostatic forces. Since ions are not capable of freely moving, ionic compounds are poor conductors of electricity in their solid state. However, in the molten state or when dissolved in water, the ions become mobile and can carry an electric charge, resulting in the compound becoming a good conductor of electricity.
Evidence 1: Sodium chloride (NaCl) is an example of an ionic compound. In its solid state, NaCl does not conduct electricity. However, when it is melted or dissolved in water, it readily conducts electricity.
Evidence 2: Magnesium oxide (MgO) is another example of an ionic compound. In its solid state, MgO is a poor conductor of electricity. However, when heated to a high temperature, the compound becomes a good conductor due to the presence of mobile magnesium and oxygen ions.
2. Covalent bonds: Covalent bonds involve the sharing of electrons between atoms. In covalent compounds, the electrons are localized between the bonded atoms and are not freely mobile. Therefore, covalent compounds tend to be poor conductors of electricity, regardless of their state.
Evidence 1: Molecular compounds like water (H2O) and carbon dioxide (CO2) consist of covalent bonds. These compounds do not conduct electricity, whether in solid, liquid, or gaseous states, because the electrons are tightly held within the molecule.
Evidence 2: Non-metals, such as sulfur (S) or phosphorus (P), form covalent compounds due to their high electronegativity. These non-metallic compounds do not conduct electricity under any conditions.
3. Metallic bonds: Metallic bonds occur in metals, where metal atoms share delocalized electrons. These electrons are free to move throughout the lattice structure, making metals excellent conductors of electricity.
Evidence 1: Copper (Cu) is a metallic substance that exhibits high electrical conductivity due to the presence of freely moving valence electrons within its lattice structure. This property makes copper widely used in electrical wiring.
Evidence 2: Aluminum (Al) is another metal known for its good electrical conductivity. Its metallic bond allows electrons to easily flow, making aluminum suitable for various electrical applications.
Overall, different bond types behave differently in terms of electrical conductivity. Ionic compounds conduct electricity when melted or dissolved, covalent compounds are poor conductors regardless of their state, and metals exhibit high electrical conductivity due to the presence of delocalized electrons. By measuring the electrical conductivity of a substance, we can determine the type of bond it possesses.