Modern Periodic Table

• Who was Dmitri Mendeleev?

  A Russian chemist and inventor
• What did Mendeleev devise in the mid-nineteenth century?

  The periodic table
• What does the periodic table organize?

  All known elements
• How did Mendeleev's periodic table predict new elements?

  By displaying patterns of chemical properties
• How are elements arranged in the periodic table?

  In order of increasing atomic number
• What does the atomic number represent?

  The number of protons in an atom
• What is included in each box of the periodic table?

  The elemental symbol, atomic number, and mass number
• What does the elemental symbol represent?

  A one or two-letter symbol for the element
• What does the mass number indicate?

  The total number of protons and neutrons
• Why did Mendeleev form a new row in the periodic table?

  Because chemical properties repeated at regular intervals
• What do we call the vertical columns in the periodic table?

  Groups
• How many groups are there in the periodic table?

  Seven groups
• What is unique about Group 0?

  It is called Group 0 instead of Group 8
• Why do elements in the same group have similar chemical properties?

  They have the same number of outer shell electrons
• How many electrons do Group 2 elements have in their outer shell?

  Two electrons
• How do Group 1 elements react with water?

  They react violently
• What are alkali metals?

  Group 1 elements with one outer shell electron
• What happens to the reactivity of Group 1 elements as you move down the group?

  They become more reactive
• What are halogens?

  Group 7 elements with seven outer shell electrons
• How does the reactivity of halogens change down the group?

  They become less reactive
• What are noble gases?

  Group 0 elements with full outer shells
• How many electrons does argon have in its outer shell?

  Eight electrons
• How many electrons does helium have in its outer shell?

  Two electrons
• Why are noble gases unreactive?

  They have full outer shells
• What does the zigzag line in the periodic table indicate?

  It separates metals from nonmetals
• What are transition metals?

  A special block of elements in the middle
• What should you remember about different types of periodic tables?

  They present the same information differently
• How can you identify the atomic number in a periodic table?

  It is the smaller of the two numbers