C2 - periodic table

• Why is the periodic table called 'periodic'?

  Elements occur at regular intervals
• What are the groups in the periodic table?

  Columns of elements with similar properties
• What types of elements are found in group one?

  Highly reactive metals like lithium
• What types of elements are found in group seven?

  Highly reactive nonmetals like fluorine
• Why do elements in the same group have similar chemical properties?

  They have the same number of outer electrons
• Who first noticed elements with similar properties occurred in threes?

  Johan Dober
• What did Dober call the groups of three elements?

  Triads
• What did John Newlands notice about the elements he arranged?

  Every eighth element reacted similarly
• What did Newlands call his observation about the elements?

  Law of octaves
• What was a problem with Newlands' law of octaves?

  Elements were grouped with different properties
• Who developed the first modern periodic table?

  Dmitri Mendeleev
• How did Mendeleev arrange the elements in his periodic table?

  By increasing atomic weight
• What two unique actions did Mendeleev take in his periodic table?

  Switched element order and left gaps
• Why did Mendeleev leave gaps in his periodic table?

  He predicted undiscovered elements' existence
• What happened when the missing elements were discovered?

  Their properties matched Mendeleev's predictions
• How are elements arranged in the modern periodic table?

  By atomic number
• What is the significance of atomic number in the modern periodic table?

  It ensures correct group placement
• What issue arises when ordering elements by atomic weight?

  Elements can appear in the wrong order
• What did Mendeleev do to address the issue of isotopes?

  He switched the order of elements
• What group was added to the modern periodic table that Mendeleev did not include?

  Group zero, the noble gases
• What are the key differences between Mendeleev's periodic table and the modern periodic table?

  • Mendeleev arranged by atomic weight; modern by atomic number
  • Modern table includes group zero (noble gases)
  • Modern table does not require switching elements
• What are the main features of the modern periodic table?

  • Arranged by atomic number
  • Organized into groups with similar properties
  • Includes metals, nonmetals, and noble gases
• What is the electronic structure of noble gases?

  They have full outer energy levels
• Why are group zero elements unreactive?

  They have full outer energy levels
• How many electrons does helium have?

  Two electrons
• How many electrons can the first energy level hold?

  Two electrons
• Why is helium stable?

  Its first energy level is full
• How many electrons does neon have?

  Ten electrons
• Why is neon unreactive?

  It has a full outer energy level
• How many electrons does argon have in its outer energy level?

  Eight electrons
• Why is argon unreactive?

  It has a full outer energy level
• What is a key fact about all noble gases?

  They all have full outer energy levels
• What is the boiling point of noble gases compared to room temperature?

  All are lower than room temperature
• How do the boiling points of noble gases vary down the group?

  They increase as relative atomic mass increases
• Which noble gas has the lowest boiling point?

  Helium
• Which noble gas has the highest boiling point?

  Radon
• Why are noble gases all gases at room temperature?

  Because their boiling points are lower
• Which groups contain highly reactive metals?

  Groups one and two
• How do transition metals compare in reactivity to metals in groups one and two?

  They are generally less reactive
• What do noble gases have that makes them unreactive?

  A full outer energy level