Modern periodic table

• How many elements are there in the periodic table?


  Approximately 100
• In what order are the elements arranged in the periodic table?


  In order of increasing atomic (proton) number
• What does the arrangement of elements in the periodic table reveal?


  It reveals repeating patterns in the properties of the elements
• What are the two main categories of elements in the periodic table?

  Metals and non-metals
• Where are metals and non-metals located in the periodic table?


  Metals are on the left and non-metals are on the right
• What are the vertical columns in the periodic table called?

  Groups
• What does the group number indicate about an element?


  It tells you how many electrons are in the outer shell
• How many electrons are in the outer shell of Group 1 elements?


  One electron
• How many electrons does Helium have in its outer shell?


  Two electrons
• Why is the number of electrons in the outer shell important?


  It determines how atoms react
• If you know the properties of one element in a group, what can you predict?


  You can predict properties of other elements in that group
• How does reactivity change in Group 1 as you go down the group?


  Reactivity increases as you go down the group
• How does reactivity change in Group 7 as you go down the group?


  Reactivity decreases as you go down the group
• What are the horizontal rows in the periodic table called?

  Periods
• What does each new period in the periodic table represent?


  Another full shell of electrons
• What are the key features of the periodic table?


  • Organizes elements by increasing atomic number
  • Reveals periodic patterns in properties
  • Distinguishes between metals (left) and non-metals (right)
  • Groups indicate outer shell electron count
  • Periods represent full electron shells