Covalent Bonding&Properties of Covalent Molecules

• What type of molecules are being discussed in this video?

  Small covalent molecules
• What are the key properties of small covalent molecules?

  • Low melting and boiling points
  • Usually gases or liquids at room temperature
  • Do not conduct electricity
• Why do small covalent molecules have low melting and boiling points?

  Because they have weak intermolecular forces
• What is the state of small covalent molecules at room temperature?

  They are usually gases or liquids
• What is the boiling point of water?

  100° C
• What happens to small covalent molecules as temperature increases?

  They vibrate more and can turn into gas
• What are intermolecular forces?

  Weak forces between molecules
• What is not broken when a substance melts or boils?

  Covalent bonds
• How does the size of a covalent molecule affect its boiling point?

  • As the size of the covalent molecule increases:

  1. Intermolecular forces increase
  2. More energy is required to break these forces
  3. Boiling point increases
• Why do small covalent molecules not conduct electricity?

  Because they do not have an overall electric charge
• What is a common exam question regarding small covalent molecules?

  Why do small covalent molecules not conduct electricity?
• What is the definition of covalent bonding?

  Covalent bonding is the sharing of electrons between atoms.
• What are the characteristics of single covalent bonds?

  • Formed by a shared pair of electrons
  • Present in small covalent molecules
  • Examples include hydrogen, chlorine, hydrogen chloride, water, ammonia, and methane
• How do double and triple covalent bonds differ from single covalent bonds?

  Double bonds share two pairs of electrons, while triple bonds share three pairs.
• What is the formula for an oxygen molecule?

  O₂
• How many electrons do oxygen atoms need to achieve a full outer energy level?

  Two more electrons.
• What is a double covalent bond?

  • Involves two shared pairs of electrons
  • Found in molecules like O₂
  • Represented by two lines in stick diagrams
• What is the formula for a nitrogen molecule?

  N₂
• How many electrons do nitrogen atoms need to achieve a full outer energy level?

  Three more electrons.
• What is a triple covalent bond?

  • Involves three shared pairs of electrons
  • Found in molecules like N₂
  • Represented by three lines in stick diagrams
• What is the formula for carbon dioxide?

  CO₂
• How many electrons does a carbon atom need to achieve a full outer energy level?

  Four more electrons.
• How many electrons do oxygen atoms need to achieve a full outer energy level in carbon dioxide?

  Two more electrons.
• How does carbon dioxide achieve covalent bonding?

  • Carbon forms a double covalent bond with each oxygen atom
  • Involves overlapping outer energy levels
  • Each atom achieves a full outer energy level
• What are the differences in bonding between O₂, N₂, and CO₂?

  • O₂: Double covalent bond (2 shared pairs)
  • N₂: Triple covalent bond (3 shared pairs)
  • CO₂: Two double covalent bonds (1 with each oxygen)
• What is a covalent bond?

  A shared pair of electrons between non-metal elements
• Why do covalent bonds occur between non-metal elements?

  Because they need to achieve full outer energy levels
• What are the characteristics of covalent bonds?

  • Strong bonds
  • Involve shared pairs of electrons
  • Occur between non-metal elements
• What is the formula for water?

  H₂O
• How many atoms of hydrogen and oxygen are in a water molecule?

  Two hydrogen atoms and one oxygen atom
• How many electrons does an oxygen atom have?

  Eight electrons
• Why are only the outer energy levels shown in bonding diagrams?

  Because only the outer energy levels are involved in chemical bonding
• What is the process of forming a water molecule through covalent bonding?

  • Hydrogen atoms require one more electron
  • Oxygen atom requires two more electrons
  • Overlapping outer energy levels
  • Sharing electrons forms two covalent bonds
• What is the dot and cross diagram used for?

  To represent covalent bonding and shared electrons in molecules
• What is the formula for ammonia?

  NH₃
• How many atoms of nitrogen and hydrogen are in an ammonia molecule?

  One nitrogen atom and three hydrogen atoms
• How many electrons does a nitrogen atom have in its outer energy level?

  Five electrons
• What is the process of forming an ammonia molecule through covalent bonding?

  • Nitrogen atom has five outer electrons
  • Each hydrogen atom has one electron
  • Sharing electrons forms three covalent bonds
• What is the formula for methane?

  CH₄
• How many atoms of carbon and hydrogen are in a methane molecule?

  One carbon atom and four hydrogen atoms