Studied by 0 people
Looks like no one added any tags here yet for you.
Why do atoms form chemical bonds
They are trying to reach the most stable state
Name the types of chemical bonds and whether they are between non-metals and metals
Ionic bonds (non-metal + metal) are formed when two atoms exchange electrons to create a positive and negative ion. Covalent bonds (Non-metal + non metal) are formed when atoms share electrons to create a molecule. Metallic bonds (metal + metal) are created when metal atoms lose their outermost electron to form positively charged ions.
Ionic bonds
1. High Melting and Boiling Points - Ionic compounds typically have high melting and boiling points due to the strong electrostatic forces of attraction between the oppositely charged ions. A significant amount of energy is required to break these bonds.
3. Electrical Conductivity - Ionic compounds conduct electricity when they are dissolved in water or melted. In solid form, the ions are fixed in place within the lattice and cannot conduct electricity. However, when melted or dissolved, the ions are free to move, allowing them to carry an electric current.
Brittleness - Ionic compounds are generally brittle. When a force is applied, the layers of ions may shift, aligning like charges together. This results in repulsion between similar charges, causing the structure to shatter instead of deforming.
Explain the properties of metallic bonds in terms of their structure and bonding
1. Electrical Conductivity - The delocalized electrons allow metals to conduct electricity efficiently. When an electric field is applied, these electrons can move freely, carrying electrical current.
3. Malleability and Ductility - Metallic bonds allow metal atoms to slide past one another without breaking the bond. This makes metals malleable (can be hammered into sheets) and ductile (can be drawn into wires).
4. Luster - The structure of metallic bonds gives metals their shiny appearance. The free electrons can reflect light, creating a lustrous surface.
5. High Melting and Boiling Points - Many metals have high melting and boiling points due to the strong attractions between the positively charged cations and the sea of electrons. A significant amount of energy is required to break these bonds.
Properties of simple covalent molecules
1. Low Melting and Boiling Points - Simple covalent molecules generally have low melting and boiling points compared to ionic or network covalent compounds. This is due to the relatively weak intermolecular forces (such as Van der Waals forces or hydrogen bonds) that hold the molecules together, requiring less energy to overcome.
3. Electrical Conductivity - Simple covalent molecules do not conduct electricity in any state (solid or liquid). This is because they do not have free-moving charged particles (ions or delocalized electrons) that are necessary for electrical conductivity.
### 4. Brittleness - Simple covalent molecules are typically soft and can be easily broken or deformed. They do not form rigid structures like ionic compounds, which contribute to their brittleness.
Explain the properties of Giant Covalent bonds
High Melting and Boiling Points - Giant covalent structures have very high melting and boiling points. This is because breaking the covalent bonds throughout the entire network requires a significant amount of energy. For example, diamond, a form of carbon, has a very high melting point due to its strong covalent bonds.
2. Hardness - Many giant covalent structures are extremely hard. The strong covalent bonds throughout the network give materials like diamond and silicon carbide their hardness, making them resistant to scratching and deformation.(except graphite)
3. Poor Electrical Conductivity - Most giant covalent structures do not conduct electricity in solid form because there are no free-moving charged particles. However, graphite (another form of carbon) is an exception, as it has delocalized electrons that allow it to conduct electricity.
Examples of giant covalent structures
Diamond: Each carbon atom forms four strong covalent bonds in a tetrahedral arrangement, resulting in a very hard material.
- Graphite: In graphite, carbon atoms are bonded in sheets of hexagonal arrangements with weak forces between layers, allowing the sheets to slide over each other. This gives graphite its lubricating properties and electrical conductivity.
- Silicon Dioxide (SiO₂): Found in quartz, silicon dioxide consists of a network of silicon and oxygen atoms connected by strong covalent bonds, resulting in a rigid and hard structure.
