Lesson 5: Mendeleev and the Periodic Table Before Lavoisier died, his plan was to have scientists find new elements – and they did. By the 1860’s, nearly 70 elements were discovered. Some elements were different, but others were similar. Why ?

Mendeleev organized the elements into a table, which showed a PERIODIC PATTERN, so it was called the Periodic Table of Elements. He even left three spaces blank and predicted what these elements would be like when they were discovered in the future – and he was right!

Modern Periodic Table Goes in order of increasing Atomic #, (# of protons) Each row going across is called a PERIOD Each column going down is called a FAMILY, elements in the same family have similar properties