Bonding and Structure Flashcards
What is ionic bonding and how does it work?
Ionic bonding is the strong electrostatic force of attraction between positive metal ions and negative non-metal ions, formed by the transfer of electrons.
What are the properties of ionic compounds?
- They form an ionic lattice in the solid state.
- High melting and boiling points due to strong electrostatic forces between ions.
- They conduct electricity only when molten or aqueous (because ions are free-moving in these states).
- They don’t conduct electricity when solid (ions are fixed in place).
Why do ionic compounds conduct electricity only when molten or aqueous?
In the solid state, ions are fixed in place and cannot move. When molten or aqueous, the ions are free-moving, allowing the compound to conduct electricity.
What is covalent bonding?
Covalent bonding is the strong electrostatic force of attraction between the positive nuclei of atoms and the negative shared electrons between them.
Why is there no attraction force between covalently bonded molecules?
There is no attraction force between covalent molecules because they are uncharged, meaning there are no opposite charges to attract each other.
What are the properties of simple covalent compounds?
- Most are gases due to weak intermolecular forces.
- Low melting and boiling points.
- Do not conduct electricity as they lack freely moving electrons or ions.
What are the properties of giant covalent structures?
- High melting and boiling points due to strong covalent bonds.
- Do not conduct electricity (except for graphite, which has free electrons).
- Examples include diamond, graphite, and silica.
Describe the structure and properties of graphite.
- Graphite consists of layers of hexagonal carbon atoms, held by weak intermolecular forces.
- The layers can slide past each other, making graphite soft and slippery.
- Graphite can conduct electricity due to the presence of free-moving electrons between layers.
Describe the structure and properties of diamond.
- Diamond has a tetrahedral structure where each carbon atom is covalently bonded to four other carbon atoms in a continuous lattice.
- This structure makes diamond hard and gives it a very high melting point.
- Diamond does not conduct electricity because it lacks free-moving electrons.
What is silica, and how does its structure contribute to its properties?
- Silica (SiO2) has a tetrahedral arrangement similar to diamond, where each silicon atom is covalently bonded to two oxygen atoms.
- This creates a strong, three-dimensional lattice with high melting points and no free electrons, so it does not conduct electricity.
What is metallic bonding?
Metallic bonding is the electrostatic attraction between positive metal ions (protons) and a sea of delocalised free-moving electrons, which move throughout the metal structure.
Why are metals ductile and malleable?
Metals are ductile and malleable because their giant metallic structure allows layers of ions to slide over each other while still being held together by delocalised electrons, which prevents the metal from breaking.
Compare ionic, covalent, and metallic bonding.
- Ionic bonding: Strong electrostatic force between positive metal ions and negative non-metal ions.
- Covalent bonding: Strong electrostatic force between positive nuclei and negative shared electron pairs.
- Metallic bonding: Positive metal ions surrounded by a sea of delocalised free-moving electrons.
