Interpreting dot and cross diagrams

• What is a covalent bond?

  A covalent bond is a shared pair of electrons.
• What do covalent bonds form?

  Covalent bonds form molecules.
• What are the properties of substances with small molecules?

  They have low melting and boiling points, and do not conduct electricity.
• What is shown in dot and cross diagrams?

  • How electrons are shared in covalent bonds
  • Representation of atoms and their bonding
• What is the charge and mass of a subatomic particle that is an electron?

  An electron has a negative charge and negligible mass relative to protons and neutrons.
• What is a double bond?

  A double bond consists of two shared pairs of electrons between two atoms.
• How many covalent bonds can oxygen atoms form?

  Oxygen atoms can form two covalent bonds.
• What is the structure of an oxygen molecule?

  The structure of an oxygen molecule is represented as O=O.
• What is the structure of a nitrogen molecule?

  The structure of a nitrogen molecule is represented as N≡N.
• How many covalent bonds can nitrogen atoms form?

  Nitrogen atoms can form three covalent bonds.
• What are the differences between single, double, and triple bonds?

  • Single bond: One shared pair of electrons
  • Double bond: Two shared pairs of electrons
  • Triple bond: Three shared pairs of electrons
• What is the formula of water?

  The formula of water is H₂O.
• How is the formula of water deduced from a dot and cross diagram?

  A water molecule is made up of one oxygen atom joined to two hydrogen atoms.
• What are the properties of substances with small molecules?

  • Low melting and boiling points
  • Do not conduct electricity