2.1 Chemical bonds: ionic, covalent, and metallic

• What are ionic bonds defined as?

  Electrostatic attraction between ions
• Ionic bonds involve the complete transfer of electrons
• Metallic bonds involve delocalized electrons
• Which two elements combine to form sodium chloride (NaCl)?

  Sodium and chlorine
• The strong electrostatic attraction between Na⁺ and Cl⁻ ions forms the ionic bond in sodium chloride.


  True
• When sodium reacts with chlorine, it forms sodium ions and chloride ions
• What is the melting point of sodium chloride (NaCl)?

  801°C
• Why do ionic compounds conduct electricity when molten or dissolved in water?

  Mobile ions
• Covalent bonds involve no complete transfer of electrons
• How do covalent bonds achieve stability in molecules?

  Electron sharing
• What type of attraction is responsible for ionic bonds?

  Electrostatic attraction
• What are the charged ions formed in ionic bonds called?

  Cations and anions
• What is the primary reason for the high melting and boiling points of ionic compounds?

  Strong electrostatic forces
• Ionic compounds conduct electricity when molten or dissolved in water
• What is the melting point of sodium chloride (NaCl)?

  801°C
• Ionic compounds are brittle because their ion layers can slide past each other.


  True
• Covalent compounds have generally low melting and boiling points
• What type of forces are responsible for the unique properties of ionic compounds?

  Electrostatic forces
• Covalent bonds typically form between non-metals
• How many hydrogen atoms share electrons with oxygen in a water molecule?

  Two
• Match the bond type with its strength and example:

  Single ↔️ Weakest, H-H

  Double ↔️ Stronger, O=O

  Triple ↔️ Strongest, N≡N
• Covalent compounds have lower melting and boiling points due to weaker intermolecular forces
• Why are covalent compounds generally poor electrical conductors?

  Electrons are tightly bound
• Metallic bonds result in a "sea" of delocalized electrons.


  True
• Ionic bonds form when a metal transfers electrons to a non-metal.

  True
• What is an example of a compound formed by covalent bonds?

  Water (H2O)
• Ionic bonds are created by the electrostatic attraction between oppositely charged ions.


  True
• When sodium reacts with chlorine, it forms sodium cations and chloride anions
• What creates positively charged ions (cations) and negatively charged ions (anions) in ionic bonding?

  Electron transfer
• Ionic compounds have high melting and boiling points due to strong electrostatic forces.


  True
• Ionic compounds are hard because of their crystal lattice structure
• Covalent bonds involve the sharing of electrons between two non-metals.


  True
• What is the primary mechanism of formation for covalent bonds?

  Sharing of electrons
• Covalent bonds form stable molecules by holding shared electrons tightly between atoms

  True
• In methane (CH₄), a carbon atom forms covalent bonds with four hydrogen atoms
• Ionic bonds involve the complete transfer of electrons


  True
• Ionic bonds form when a metal donates electrons to a non-metal
• What charge do metal ions typically have in ionic bonds?

  Positive
• The crystal lattice structure of ionic compounds makes them resistant to deformation

  True
• Match the bond type with its properties:

  Ionic ↔️ High melting point, hard

  Covalent ↔️ Low melting point, soft