Ionic, covalent and metallic bonds

• Non-metals tend to form negative ions by gaining electrons.
• Metals tend to form positive ions by losing electrons.
• Ions are charged particles formed when atoms gain or lose electrons.
• When two atoms of potassium react with one atom of sulfur in terms of electron transfer

  Electrons are transferred from potassium to sulfur. Two potassium atoms each lose one electron forming K+, sulfur atoms gain 2 electrons forming S2−
• One reason why the ball and stick model is not a true representation of the structure of potassium sulfide
• Explanation of why pure water does not conduct electricity in terms of bonding

  Because pure water is covalent so it has no free electrons as there are no ions present
• Explanation for aluminium ions moving to the negative electrode

  Oxygen aluminium ions are positive so are attracted
• Explanation of how electricity is conducted in a metal

  Giant lattice made up of atoms with delocalized electrons so can move and carry charge
• When a sodium atom reacts with a chlorine atom to produce sodium chloride

  Sodium loses electrons, chlorine gains 1 electron
• Reason why silicon dioxide is used as the inside layer of furnaces
• How copper compounds are extracted by phytomining

  Copper compounds are absorbed by plants which are burned. The ash contains the copper compounds
• Explanation of why sodium chloride solution conducts electricity

  As there are ions in sodium chloride which can move and carry charge
• Reason why this alloy is harder than the pure metal

  The atoms are different sizes so they can’t slide past each other
• Explanation of how a catalyst increases the rate of the reaction

  Because a catalyst provides an alternative pathway that has a lower activation energy
• Anions have a negative charge because they have gained one or more electrons.
• Cations have a positive charge because they have lost one or more electrons.
• Explain why this alloy is harder than the pure metal

  The atoms are different sizes so they can’t slide each other
• Describe, in terms of electrons, what happens when a sodium atom reacts with a chlorine atom to produce sodium chloride

  Sodium loses electrons chlorine gains 1 electron
• Aluminium ions move to the negative electrode. Explain why.

  Oxygen aluminium ions are positive so are attracted
• Silicon dioxide is used as the inside layer of furnaces. Suggest why.

  4 covalent bonds
• Describe what happens when two atoms of potassium react with one atom of sulfur. Give your answer in terms of electron transfer. Give the formulae of the ions formed.

  electrons transferred from potassium to sulfur, two potassium atoms each lose one electron forming K+ sulfur atoms gain 2 electrons forming S2−
• The ball and stick model is not a true representation of the structure of potassium sulfide. Give one reason why.

  There are no gaps between ions
• Explain how electricity is conducted in a metal

  Giant lattice made up of atoms with delocalized electrons so can move and carry charge
• Explain, in terms of bonding, why pure water does not conduct electricity

   

  Because pure water is covalent so pure water has no free electron as there are ions in sodium chloride
• Explain why sodium chloride solution conducts electricity

  As there are ions in sodium chloride which can move and carry charge
• Describe how copper compounds are extracted by phytomining

  Copper compounds are absorbed by plants which are burned

  The ash contains the copper compounds

   
• Explain how a catalyst increases the rate of the reaction.

  because a catalyst provides an alternative pathway that has a lower activation energy