Page 1 - 3. Lesson Notes Ch-5 MENDELEEVES CLASSIFICATION

SAI International School
Class-X

Subject_ Chemistry
Ch- Periodic Classification
Sub topic- Mendeleev's Periodic Classification

Lesson Notes

To be done in CW Copy-

➢ Mendeleev's Periodic Classification
Dmitri Ivanovich Mendeleev, a Russian scientist arranged the elements in
increasing order of their relative atomic masses.

He was honoured with Noble prize in 1906 for his Periodic Table.

 Mendeleev arranged all 63 elements; which were discovered till his time; in
the order of their increasing relative atomic masses.

 This is known as Mendeleev’s Periodic Table.

He divided the table into eight columns and seven rows.

a. The columns are known as groups,
b. The rows are known as periods.

On doing so, he observed that the properties of elements were repeated at
regular intervals.

He arranged the elements such that elements with similar properties fell into the
same vertical columns of the periodic table.

• Explanation of Mendeleev’s Periodic Table:

 Elements are arranged in the periodic table in the increasing order of their
relative atomic masses.
 Mendeleev divided his periodic table in eight groups and seven periods.
 Groups from I to VII are meant for normal elements and group VIII is for
transition elements.
 Periods from 4th to 7th have been divided in two series: 1st series and 2nd
series.
 Elements having similar properties have been kept in the same group. For
example; lithium, potassium, rubidium, etc. are in 1st group.

1