Structure and bonding.

• Elements react in order to achieve a full outer energy level.
• When a metal and a non metal react ionic bonding takes place.
• What happens when we react a group 1 atom with a group 7 atom?

  Group 1 atom loses its outer electron, this gives both atoms a full outer energy level.
• During ionic bonding group 1 metals lose one electron forming a positive one ion.
• During ionic bonding group 7 non metals gain one electron forming a negatice one ion.
• During ionic bonding group 2 metals lose 2 electrons forming a positive two ion.
• During ionic bonding group 6 non metals gain two electrons forming a negative two ion.
• Ionic compounds form giant structures.
• What do scientists call these giant structures?

  Giant ionic lattice.
• What is every positive ion in a giant ionic lattice surrounded by?

  Negative ions - and every negative ion is surrounded by positive ions.
• Giant ionic lattices are three dimensional structures.
• What do scientists call the attraction between positive and negative ions?

  Electrostatic forces of attraction.
• Electrostatic forces of attraction hold positive and negative ions in place.
• Features of ionic compounds.

  1. High melting and boiling points.
  2. As electrostatic forces require a great deal of energy to break.
• Key features of ionic compounds.

  1. Cannot conduct electricity when solid as when they are solid they are locked in place by the strong electrostatic forces of attraction.
  2. They can in water as the ions can now move and carry electrical charge.
• A covalent bond is a strong bond.
• Covalent bonding occurs with non metals.
• What is a double covalent bond?

  A chemical bond formed when two atoms share two pairs of electrons.
• What is a triple covalent bond?

  A triple covalent bond is a type of chemical bond formed between atoms where three pairs of electrons are shared.
• A triple covalent bond is the strongest type of covalent bond.
• Small covalent molecules have low melting and boiling points.
• Small covalent molecules are usually gases or liquids at room temperature.
• Explain why small covalent molecules have low melting and boiling points?

  1. Atoms are held together by strong covalent bonds.
  2. There are weak intermolecular forces between molecules.
  3. If we increase the temperature vibrations increase to a point where they break intermolecular forces turning the covalent molecule into a gas.
• Intermolecular forces do not require a lot of energy to break.
• Small covalent molecules do not conduct electricity as they do not have an overall electric charge.
• Giant covalent substances are always solids at room temperature.
• Why are giant covalent substances solid at room temperature?

  Because they have high melting and boiling points as they have millions of strong covalent bonds so it takes a lot of energy to break these covalent bonds.
• What element is diamond formed from?

  Carbon.
• Diamond contains a huge number of carbon atoms joined by covalent bonds.
• Why does it take a great deal of energy to melt diamond?

  Because we would have to break the millions of covalent bonds within diamonds.
• The melting point of diamond is over 3700 degrees celcius.
• Why can't diamond conduct electricity?

  As all of the outer electrons are in covalent bonds there are no free electrons to carry out electrical charge.
• What elements does silicon dioxide contain?


  Silicon and oxygen covalently bonded together.
• Silicon dioxide has a very high melting and boiling point as it has a strong number of covalent bonds.
• What element is graphite made from?

  Carbon.
• Graphite is also a giant covalent molecule.
• Graphite is soft and slippery.
• Graphite has a very high melting and boiling point.
• Graphite is a good conductor of electricity and heat.
• In graphite each carbon atom forms covalent bonds to three other carbon atoms.