1. The Modern Periodic Table Chapter 5
History

2. Chapter 5 – The Periodic Law
By 1860, over ____ elements had been discovered.
Scientists were using different _______ ________ for the elements.
They got together and decided on the ________ ________ _________. 60
atomic
masses
average
atomic
masses

3. Dmitri Mendeleev and Periodicity
Noticed that when elements were arranged in order of ___________ ________ _______, certain similarities in ___________ occurred at regular intervals.
Such a repeating pattern is referred to as ___________.
He created the first periodic table based on ________ __________.
increasing
atomic
mass
properties
periodicity
atomic
masses

4. The first published periodic table by Mendeleev

5. Henry Mosely and the Periodic Law
In 1911, he was working with ____________.
He noticed a pattern when elements were arranged in increasing nuclear _________ (# of ________).
This work lead to the modern definition of ________ _________.
The periodic table is now arranged according to ________ _________.
Rutherford
charge
protons
atomic
number
atomic
number

6. Periods of the Periodic Table
________ across the periodic table
There are ____ periods.
Rows 7

7. Groups of the periodic table
families
also called ___________
the _________ (up & down) of the periodic table.
elements of the same group have similar _________.
There are ___ groups
Groups 1, 2, 13, 14, 15, 16, 17, 18 also called: ______________________________
columns
properties 18
1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A