Simple Molecular Substances

• What are simple molecular substances made up of?

  Molecules containing a few atoms
• Why is it important to know about simple molecular substances?

  They are fundamental components of matter
• How many electrons do hydrogen atoms have?

  One electron
• What do hydrogen atoms need to complete their first shell?

  One more electron
• How do hydrogen atoms typically bond with other atoms?

  By forming single covalent bonds
• What is the molecular formula for oxygen gas?

  O₂
• How many electrons does each oxygen atom need to complete its outer shell?

  Two more electrons
• How do two oxygen atoms bond together?

  By sharing two pairs of electrons
• What is the molecular formula for methane?

  CH₄
• How many outer electrons does carbon have?

  Four outer electrons
• How many covalent bonds can carbon form with hydrogen atoms?

  Four covalent bonds
• What is the molecular formula for ammonia?

  NH₃
• How many electrons does nitrogen need to complete its outer shell?

  Three more electrons
• How do nitrogen atoms bond in ammonia?

  By forming three covalent bonds
• What is the molecular formula for chlorine gas?

  Cl₂
• How many electrons does each chlorine atom need to complete its outer shell?

  One more electron
• How do two chlorine atoms bond together?

  By sharing one pair of electrons
• What is the molecular formula for nitrogen gas?

  N₂
• How many electrons does each nitrogen atom need to complete its outer shell?

  Three more electrons
• How do two nitrogen atoms bond together?

  By sharing three pairs of electrons
• What is the molecular formula for water?

  H₂O
• How many electrons do oxygen atoms share with hydrogen atoms in water?

  Two pairs of electrons
• How do hydrogen atoms bond with oxygen in water?

  By forming two single covalent bonds
• What is the molecular formula for hydrogen chloride?


  HCl
• How does hydrogen chloride bond?

  By sharing one pair of electrons
• What are the properties of simple molecular substances?

  • Low melting and boiling points
  • Usually gases or liquids at room temperature
  • Poor electrical conductivity
  • Often soluble in non-polar solvents
• What are the common types of simple molecular substances?

  • Hydrogen (H₂)
  • Oxygen (O₂)
  • Methane (CH₄)
  • Ammonia (NH₃)
  • Chlorine (Cl₂)
  • Nitrogen (N₂)
  • Water (H₂O)
  • Hydrogen chloride (HCl)
• What forms when two hydrogen atoms bond together?

  A pair of electrons
• What is similar between hydrogen chloride and H₂?

  Both involve two atoms forming bonds
• How many electrons do hydrogen and chlorine atoms need to complete their outer shells?

  One more electron
• What are the properties of simple molecular substances?

  • Usually have simple molecular structures
  • Examples include hydrogen chloride and H₂
• What holds atoms together within molecules?

  Very strong covalent bonds
• How do intermolecular forces compare to covalent bonds?

  Intermolecular forces are very weak
• What must you do to melt or boil a simple molecular compound?

  Break intermolecular forces
• What state are most simple molecular substances at room temperature?

  Gases or liquids
• What happens to intermolecular forces as molecules get larger?

  The strength of intermolecular forces increases
• Why do larger molecules require more energy to break intermolecular forces?

  Because the strength of forces increases
• What do molecular compounds not conduct?

  Electricity
• Why don't molecular compounds conduct electricity?

  They aren't charged
• What are the characteristics of molecular compounds?

  • Do not conduct electricity
  • Low melting and boiling points
  • Often gases or liquids at room temperature