Developing the periodic table

• Summary of Mendeleev's work

  1. All elements with similar properties are placed in the same vertical columns

  2. He left gaps in the table for undiscovered elements

  3. He predicted the properties of these undiscovered elements

  4. He reversed the order of some elements so they would fall within the correct group of elements
• Dmitri Mendeleev

  When elements are arranged in order of increasing atomic weight(relative atomic mass), the properties of the elements recur periodically.

  
• Period number indicates


  number of shells
• groups show the

  number of electrons in the outer shell
• non-metals are on the

  right
• metals are on the

  left
• Groups

  vertical columns
• Periods

  horizontal rows
• what mendeleev do to the periodic table

  he left gaps for new elements
• what was wrong with the periodic table

  some elements were in the wrong group
• why wasn't the periodic table complete

  some elements had not been discovered
• in the early 1800s how were elements arranged

  by atomic mass
• Mendeleev predicted 3 elements properties based off of his periodic table. They were discovered between 1876 and 1886. They were found to have similar properties the ones he had predicted.