periodic table

• Who devised the Periodic Table?

  Dimitri Mendeleev
• In which century was the Periodic Table developed?

  Mid 19th century
• What was the main purpose of Mendeleev's Periodic Table?

  To organize the known elements
• What did Mendeleev predict about the elements?

  He predicted new elements
• How are elements arranged in the Periodic Table?

  From left to right by increasing atomic number
• What is the approximate mass number of sodium (Na)?

  23
• What does the symbol "Na" represent?

  Sodium
• What are the main structural features of the Periodic Table?

  • Organized into periods and groups
  • Periods: horizontal rows
  • Groups: vertical columns
  • Elements in the same group have similar chemical properties
• What does it mean for elements in the same group to have the same number of electrons?

  They exhibit a pattern of chemical properties
• Which group in the Periodic Table contains noble gases?

  Group 8
• What is a characteristic of noble gases?

  They are unreactive
• What is the significance of the outer shell in noble gases?

  It is full, making them stable and unreactive