The Periodic Table

• Who created the Periodic Table?

  Mendeleev
• Why did Mendeleev leave gaps in the Periodic Table?

  To keep the groups together
• What happened when new elements were discovered?

  They filled the gaps in the table
• What does the discovery of isotopes explain?

  Why elements can't be ordered by atomic weight
• What are the general reactivity trends of metals and non-metals?

  • Metals: don't generally react
  • Non-metals: tend to get a full outer shell
  • More reactive when they have fewer electrons in the outer shell
• How are elements ordered in the Periodic Table?

  By increasing atomic number
• What are the horizontal rows in the Periodic Table called?

  Periods
• Why did Mendeleev swap some elements around?

  To fit the pattern of properties
• What can you predict if you know how one element in a group reacts?

  • You can predict how others will react
  • Elements with similar properties form vertical groups
• What does the position in the periodic table indicate about an element's electronic structure?

  It indicates the number of electrons in shells
• What does the period number represent in the Periodic Table?

  The number of electrons in the outer shell
• What does the group number represent in the Periodic Table?

  The number of shells with electrons in
• What properties are compared in the Periodic Table?

  • Appearance
  • Strength
  • Melting point
  • Boiling point
  • Conductivity