• The Russian scientist DMITRI MENDELEEV is considered to be the father of the modern periodic table, created in 1869 .
• Mendeleev wrote the know properties of the elements on cards and laid them out in a grid by
INCREASING ATOMIC MASS .
• He noticed that the properties of the elements tended to repeat EVERY 8 th ELEMENT .

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• When the properties REPEATED , he came back and started a NEW ROW …..
Blank Blank
Space Space
Blank
Space
• Sometime he had to leave a BLANK SPACE in order to keep the properties aligned.

• Mendeleev said the blank spaces were
ELEMENTS NOT YET DISCOVERED .
• Years later, minor problems lead HENRY
MOSELEY to rearrange the table by
INCREASING ATOMIC NUMBER instead of atomic mass number.
• The modern table is still arranged this way.

• The Periodic Table (PT) is a series or ROWS and
COLUMNS of small squares known as ELEMENT KEYS .
• ROWS run LEFT TO RIGHT and are known as PERIODS or SERIES.
• All element in a period or series have the SAME
NUMBER of ELECTRON ENERGY LEVELS .
• There are 7 ROWS across the periodic table.
– Numbered 1 (Hydrogen) down to 7 (Francium)

• COLUMNS run UP and DOWN vertically on the periodic table.
• A columns is known as GROUP or a FAMILY .
• All elements in a group or family have the
SAME NUMBER of ELECTRONS in the
OUTERMOST LEVEL of their electron cloud.
– The number and arrangement of outermost electrons determines the chemical and physical properties of an element.
– The outermost energy level of the electron cloud is called the VALENCE ENERGY LEVEL .

• The next few slides deal with numbering and labeling the periodic table.
• IF YOU HAVE TROUBLE FOLLOWING THE
DIRECTIONS FOR LABELING, refer to the LAST
SLIDE which is a completed sample periodic table.
• You completed table should look like this!

• 1. NUMBER the PERIODS/SERIES (left to right rows) ON THE LEFT SIDE from 1 (beside
Hydrogen) to 7 (beside Francium).
• Normally, periods and series DO NOT HAVE
NAMES . The exceptions are the TWO ROWS at the bottom of the table.
– The first row (La) is called the LANTHANIDE
SERIES
– The second row (Ac) is the ACTINIDE SERIES .
– Together, these are the RARE EARTH ELEMENTS .

• The GROUPS or FAMILIES (vertical columns) are numbered ABOVE THE TOP BLOCK from 1
(beginning at Hydrogen) to 18 (Helium).
– Number the columns across the periodic table.
• Unlike the PERIODS or SERIES, the GROUPS and FAMILIES do have NAMES.
• Write the NAME of each family in the blank above the column.

• GROUP 1 – Alkali Metals
• GROUP 2 – Alkaline Earth Metals
• GROUPS 3-12 – together are called the
TRANSITION METALS
• GROUP 13 – Boron Family
• GROUP 14 – Carbon Family
• GROUP 15 – Nitrogen Family
• GROUP 16 – Oxygen Family
• GROUP 17 – Halogen Family
• GROUP 18 – Noble Gas Family