- Periodic Table: The periodic table is the intersection of columns and raws to contain elements on the basis of certain defined properties.
- The scientific classification of elements to make its study easy is called periodic table.
- Periodic Table:-
- Old or short form or Mendleev periodic Table
- Modern or long form or Mosely periodic table.
- Older short form periodic table and Modern/ long form periodic table.
|Old Periodic Table||Modern Periodic Table|
|1. The physical and chemical properties of elements are periodic function of their atomic weight.||1. The physical and chemical properties of elements are periodic function of atomic numbers.|
|2. Elements are arranged on the basic of increasing atomic weights.||2. Elements are arranged on the basis of increasing atomic numbers.|
|3. It is designed by Russian scientist – Mendleev||3. It is designed by English scientist – Moseley.|
|4. It contains only 63 elements.||4. It contains 118 elements.|
|5. It has seven (1-7) periods and eight (I-VIII) groups.||5. It contains seven periods and 9 groups. There are 18 groups including sub-groups.|
a. Hydrogen is non-metal but placed with metals.
b. The place of isotopes are not determined.
c. The place of lanthanides and table actinides are not justified.
a. Hydrogen is the non-metal but placed with metals.
b. The lanthernides and actinides are placed at the bottom of periodic table.
|7. Advantage:||7. Advantage:
a. The place of isotopes are determined.
b. The place of lanthenidies and actinides are justified.
c. These elements of similar properties are placed in similar groups.
- also read about surface tension chemistry notes