Chemistry Periodic Table

• What are the first three alkali metals?

  Lithium, Sodium, Potassium
• What are the reactions of the first three alkali metals with water?

  • Lithium: fizzing, floats, disappears, produces LiOH
  • Sodium: fizzing, floats, moves rapidly, produces NaOH
  • Potassium: fizzing, purple flame, floats, produces KOH
• What gas is produced when alkali metals react with water?

  Hydrogen gas
• What type of solution is produced when alkali metals react with water?

  Alkaline solution
• What is the nature of the reactions of alkali metals with water?

  They are exothermic reactions
• Why does reactivity increase down group 1?

  • Increased distance from nucleus to outer electron
  • Increased shielding by inner electrons
• What do halogen elements exist as?

  Diatomic molecules
• What are the physical properties of halogens at room temperature?

  • Fluorine: pale yellow gas
  • Chlorine: green/yellow gas
  • Bromine: brown/orange/red liquid
  • Iodine: grey solid
• What trend is observed in halogens as you go down the group?

  They get darker in color
• What happens to the melting and boiling points of halogens down the group?

  They increase down the group
• What do halogen elements form when they react with metals?

  Halide compounds
• Why does reactivity decrease down group 7?

  • Greater distance from nucleus to outer energy level
  • Increased shielding by inner electrons
• What occurs when a halogen displaces a less reactive halogen from a compound?

  A darker color is observed
• What are the general properties of typical metal elements?

  • Hard, dense, malleable, ductile
  • High melting and boiling points
  • Good conductors of heat and electricity
  • Unreactive
• What are the general properties of non-metal elements?

  • Brittle, low melting and boiling points
  • Poor conductors of heat and electricity
• Why are noble gases unreactive?

  They have full outer electron levels
• What is the trend of boiling points in group 0 elements?

  They increase down the group
• What is the trend of density in group 0 elements?

  They increase down the group
• What do transition metals normally form?

  Coloured compounds
• How are alkali metals different from typical metals?

  • Soft and can be cut easily
  • Low density and float on water
  • Very reactive
• What happens to the melting point of alkali metals going down the group?

  It decreases
• What are the reactions of the first three alkali metals with oxygen?

  • Lithium: red flame, produces Li2O
  • Sodium: yellow flame, produces Na2O
  • Potassium: purple flame, produces K2O
• What are the reactions of the first three alkali metals with chlorine?

  • Lithium: red flame, produces LiCl
  • Sodium: yellow flame, produces NaCl
  • Potassium: purple flame, produces KCl
• Why are elements placed in a group in the periodic table?

  They are similar to each other
• What does the group number indicate in the periodic table?

  Number of outer electrons
• What does the period number indicate in the periodic table?

  Number of energy levels
• What is the trend of atomic radius going down a group?

  It increases
• What is the trend of pH of compounds formed by elements when they react with water?

  • Group 1 and 2: alkaline (pH 8 to 13)
  • Group 6 and 7: acidic (pH 1 to 6)
• How did Dalton arrange elements?

  By atomic weight
• What did Newlands identify in his arrangement of elements?

  Law of Octaves
• What was a problem with Newlands' Law of Octaves?

  Many elements did not fit the pattern
• How did Mendeleev improve upon Newlands' arrangement?

  He left gaps for undiscovered elements
• What did Mendeleev predict about undiscovered elements?

  Properties and atomic weights
• What is the modern Periodic Table based on?

  Atomic number