C2

• How are elements in the periodic table arranged?

  In order of atomic number
• Why is the periodic table named this?

  Elements with similar properties occur at regular periods
• Why do elements in the same group have similar properties?

  They have the same number of valence electrons
• How were elements arranged in the past?

  In increasing order of atomic mass
• What were the problems with early periodic table?

  Incomplete, not all elements were discovered

  inaccurate, when elements were placed in order of atomic mass, they ended up in the same group
• How did Mandeleev overcome the problems of the early periodic table?

  Leaving gaps for undiscovered elements and changing the order of some elements
• What type of ions do metals form?

  Positive ions
• What types of ions do non-metals form?

  Negative ions
• Where are metals found in the periodic table?

  Bottom left
• Where are non-metals found in the periodic table?

  Top right
• What are elements in group 0 known as?

  Noble gases
• Why are the elements in group 0 unreactive?

  They have full outermost shells
• Why are elements in group 0 monoatomic?

  They have a full outer shell and do not lose nor gain electrons
• What happens to the boiling point as you go down group 0?

  Increases
• What are the elements in group 1 called

  Alkali metals
• What happens to reactivity down group 1

  increases
• Why does reactivity increase down group 1

  Down the group, the atoms get bigger creating more of a distance and weakening the attraction between the nucleus and electrons, making it easier to lose electrons.
• Group 1 element reaction with oxygen

  Alkali metal + Oxygen → Metal Oxide
• Group 1 element reaction with Chlorine

  Alkali Metal + Chlorine → Metal Chloride
• Group 1 element reaction with water

  Alkali metal + Water → Metal Hydroxide + Hydrogen
• What are the elements in group 7 called?

  Halogens
• What happens to reactivity down group 7?

  Decreases
• Why does reactivity decrease down group 7?

  Due to weaker attraction between nucleus as atom gets bigger, making it harder to lose electrons
• What colour vapour does fluorine have?

  Yellow
• What colour vapour does Chlorine have?

  Green
• What colour vapour does bromine have?

  Red-Brown
• What colour vapour does iodine have?

  Purple
• What is ionic bonding?

  Ionic bonding is the electrostatic attraction between positive and negative ions.
• Why is ionic bonding considered a strong attraction?

  It involves strong electrostatic forces between oppositely charged ions.
• How are ionic compounds held together?

  • They are held together in a giant lattice.
  • It’s a regular structure that extends in all directions.
  • Electrostatic attraction between positive and negative ions holds the structure together.
• What are the properties of ionic substances?

  • High melting and boiling points due to strong electrostatic forces.
  • Do not conduct electricity when solid (ions in fixed positions).
  • Conduct electricity when molten or dissolved in water (ions are free to move).
• What is important when working out a formula of an ionic compound?

  Ionic compounds are electrically neutral; positive and negative charges must balance each other.
• How are ionic compounds formed? Explain in terms of MgO case.

  • Reaction of a metal with a non-metal.
  • Electron transfer occurs; metal gives away its outer shell electrons to non-metal.
  • Mg becomes Mg^2+ and O becomes O^2- (oxide).
• What is a covalent bond?

  A covalent bond is a shared pair of electrons between two atoms.
• Describe the structure and properties of simple molecular covalent substances.

  • Do not conduct electricity (no ions).
  • Composed of small molecules.
  • Weak intermolecular forces lead to low melting and boiling points.

  
• How do intermolecular forces change as the mass/size of the molecule increases?

  Intermolecular forces increase, causing melting/boiling points to increase as well.
• What are polymers? What are thermosoftening polymers?

  • Polymers are very large molecules with atoms linked by covalent bonds.
  • Thermosoftening polymers melt/soften when heated; no bonds between polymer chains.
• What are giant covalent substances? Give examples.

  • Solids with atoms covalently bonded in a giant lattice.
  • High melting/boiling points due to strong covalent bonds.
  • Examples: Diamond, graphite, silicon dioxide.

  
• Describe and explain the properties of allotropes of carbon.

  • Diamond: Very hard, high melting point, does not conduct electricity.
  • Graphite: Soft, high melting point, conducts electricity due to delocalised electrons.
  • Fullerenes: Hollow molecules based on hexagonal rings.
  • Nanotubes: High tensile strength, conductivity.
  • Graphene: A single layer of graphite.
• What is metallic bonding?

  Metallic bonding is the attraction between delocalised electrons and the nuclei of metal ions.