Covalent

• What does covalent bonding happen between

  A non metal and a non metal
• Do covalently bonded substance have a high or low melting/boiling point

  Low
• how do the atoms complete their outer shell in covalent bonding

  by sharing electrons
• what are the two substances that use covalent bonding

  simple molecules and giant covalent structures
• How do you represent/draw covalently bonded substances

  dot and cross diagrams that look like venn diagrams
• Give 3 examples of simple molecular substances

  Oxygen(O2), water (H20), Carbon dioxide (CO2)
• what are simple molecules

  molecules that contain only a few atoms
• what state are most covalent substances

  mostly gas or liquid but sometimes a solid
• What are the atoms in a molecule held together by

  Strong covalent bonds
• What are the molecules held together by

  Weak intermolecular forces
• What are 2 properties of small molecules

  -Low melting and boiling point

  -Don’t conduct electricity
• properties of molecular solids

  -Low melting point and boiling point

  -Are usually soft and brittle

  -insoluble in water but can be dissolved in othe substances like petrol
• covalent bonds are not broken, weak intermolecular forces are overcome
• Why do small molecules have low melting points

  -They have weak intermolecular forces between molecules

  -they require little energy to overcome

  -Therefore low temperatures can boil or melt these small molecules
• Why don’t covalent substances conduct electricity

  because they don’t contain charged particles