The Periodic Table

Mendeleev’s Table 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 8th ELEMENT.

When the properties REPEATED, he came back and started a NEW ROW….. Blank Blank Blank Space Space 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.

Parts of the Periodic Table 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.

Labeling the Periodic Table 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!

LABELING the Periodic Table 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.

Unlike the PERIODS or SERIES, the GROUPS and FAMILIES do have NAMES. 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