Periodic table and history of the atom

• What are the alkali metals in Group 1?

  Lithium, sodium, and potassium
• Why are alkali metals stored in oil?

  To prevent reaction with air and moisture
• What is the outer electron configuration of alkali metals?

  One outer electron
• What are the physical properties of alkali metals?

  Silver, shiny, low melting point, soft
• How do alkali metals react with water?


  They produce hydroxide and hydrogen gas
• What is the balanced equation for sodium reacting with water?

  2Na + 2H₂O → 2NaOH + H₂
• What do alkali metals form when they react with non-metals like chlorine?

  Soluble ionic solids
• What is the balanced equation for sodium reacting with chlorine gas?

  2Na + Cl₂ → 2NaCl
• How does the size of alkali metal atoms affect their reactivity?

  Larger atoms have outer electrons further from nucleus
• Which alkali metal is the most reactive?

  Potassium
• What flame color does lithium produce?

  Crimson/red
• What flame color does sodium produce?

  Yellow/orange
• What flame color does potassium produce?

  Lilac/purple
• What are the halogens in Group 7?

  Chlorine, bromine, and iodine
• What type of bonds do halogens form?

  Covalent bonds in simple molecules
• What is the charge of halide ions?

  1. charge
• How does the size of halogen molecules affect their melting and boiling points?

  Increases with larger molecules due to IMF
• What do halogens form when they react with metals?

  White, soluble ionic compounds called halides
• What is the balanced equation for sodium reacting with chlorine gas to form sodium chloride?

  2Na + Cl₂ → 2NaCl
• What happens when a more reactive halogen displaces a less reactive halogen?

  It forms a new compound with the less reactive halogen
• What is the balanced equation for chlorine reacting with potassium iodide?

  Cl₂ + 2KI → I₂ + 2KCl
• How does the reactivity of halogens change down the group?

  Decreases from fluorine to iodine
• What are the properties of noble gases?

  Colorless, unreactive, full outer shell
• Why are noble gases considered stable?

  They have a full outer shell of electrons
• What are the uses of noble gases?

  Lighting, welding, MRI scanners, lasers
• What are the characteristics of transition metals?

  Hard, shiny, high melting point, good conductors
• Why are transition metals used as catalysts?

  They have different valencies and good conductivity
• How is the periodic table arranged?

  By increasing proton number
• What does each group in the periodic table represent?

  Same number of outer electrons
• What does each period in the periodic table represent?

  Number of electron shells
• What information does each symbol in the periodic table provide?

  Proton number and mass number
• How did Mendeleev arrange the periodic table?

  By atomic weight and reactivity
• What did Mendeleev predict about undiscovered elements?

  Left gaps for them in the table
• What was the Plum Pudding Model of the atom?

  Atom has a weak positive charge with electrons
• What did Rutherford's experiment reveal about the atom?

  Strong positive charge concentrated in nucleus
• What is the current model of the atom based on Bohr's theory?

  Electrons in shells with nothing in between
• What is the mass number of a proton?

  1 amu
• What is the mass of an electron?

  1/2000 amu
• What is the charge of a proton?

  +1
• What is the charge of an electron?

  • 1