Chemical bonds

• What type of bond forms between non-metal elements?

  Covalent bonds
• What is a giant covalent structure?

  It is a structure where atoms are joined by covalent bonds over a large number of atoms.
• What is a covalent bond?

  A covalent bond is a shared pair of electrons between non-metal atoms.
• Why do covalent compounds have low melting and boiling points?

  They have weak intermolecular forces, requiring little energy to break them.
• What state are most covalent compounds at room temperature?

  They are gases or liquids.
• Why can't covalent compounds conduct electricity?

  They have no free-moving ions.
• What is a single covalent bond?

  It is one shared pair of electrons.
• What is a double covalent bond?

  It is two shared pairs of electrons.
• What is a triple covalent bond?

  It is three shared pairs of electrons.
• What is diamond in terms of its structure?

  Diamond is an allotrope of carbon where each carbon atom is bonded to four other carbon atoms.
• What is silicon dioxide made of?

  Silicon dioxide is made of silicon and oxygen with many strong covalent bonds.
• What are the properties of silicon dioxide?

  It has a high melting and boiling point due to strong covalent bonds.
• What is graphite in terms of its structure?

  Graphite is an allotrope of carbon where each carbon atom is connected to three other carbon atoms.
• How are the carbon atoms arranged in graphite?

  They are arranged in hexagonal layers with weak intermolecular forces between the layers.
• What is graphene?

  Graphene is a single sheet of graphite with strong covalent bonds between carbon atoms.
• What are the properties of graphene?

  Graphene can conduct electricity and is very lightweight.
• What are carbon nanotubes?

  Carbon nanotubes are rolled sheets of graphene that can conduct electricity.
• What happens when metals react with non-metals?

  Metals lose electrons to achieve a full outer shell while non-metals gain electrons.
• What do metals form when they lose electrons?

  Metals form cations.
• What do non-metals form when they gain electrons?

  Non-metals form anions.
• What is an ionic lattice?

  An ionic lattice is a regular crystal structure formed by oppositely charged ions.
• How are ions held together in an ionic lattice?

  They are held together by electromagnetic forces.
• What is the appearance of most ionic compounds?

  They are mostly white solids, but transition metals can be colorful.
• What is the solubility of ionic compounds in water?

  They are easily dissolved in water to form aqueous solutions.
• What are the melting and boiling points of ionic compounds?

  They have high melting and boiling points.
• What is metallic bonding?

  Metallic bonding occurs between metal atoms where they lose electrons and become positive ions surrounded by delocalised electrons.
• What are the properties of metals due to delocalised electrons?

  Metals are good conductors of electricity and heat.
• Why can metals be bent and shaped?

  The layers of atoms can slide over each other due to the arrangement of positive metal ions and delocalised electrons.
• What is an alloy?

  An alloy is a mixture of two or more different metals.
• Why are alloys harder than pure metals?

  Alloys have distorted layers due to different sized metal atoms, making it harder for layers to slide over each other.
• What are shape memory alloys?

  Shape memory alloys can return to their original shape after being deformed.
• Why do metals have high melting and boiling points?

  Because metallic bonds are strong and require a lot of energy to break.
• What happens to electrons in metallic bonding?

  The electrons become delocalised and are free to move.
• What is the structure of pure metals and alloys?

  They have a metallic bonding structure where positive metal ions are surrounded by delocalised electrons.
• What is the role of delocalised electrons in metals?

  Delocalised electrons allow metals to conduct electricity and heat.
• How do delocalised electrons contribute to the properties of metals?

  They carry charge and kinetic energy, allowing metals to conduct electricity and heat.
• What happens to the layers of atoms in alloys?

  The layers are distorted by different sized metal atoms, making it harder for them to slide over each other.
• What is the significance of delocalised electrons in the context of metallic bonding?

  Delocalised electrons allow for the conductivity and malleability of metals.
• What is the effect of temperature on the properties of metals?

  Metals have high melting and boiling points, requiring a lot of energy to change states.
• What is the relationship between metallic bonding and the physical properties of metals?

  The strong metallic bonds contribute to the high melting and boiling points of metals.