| 1 |
Elements are arranged in the increasing order of their atomic masses. |
1 |
Elements are arranged in the increasing order of their atomic numbers. |
| 2 |
There are a total of 7 groups (columns) and 6 periods (rows). |
2 |
There are a total of 18 groups (columns) and 7 periods (rows). |
| 3 |
Elements having similar properties were placed directly under one another. |
3 |
Elements having the same valence shell are present in the same period while elements having the same number of valence electrons are present in the same group. |
| 4 |
The position of hydrogen could not be explained. |
4 |
Hydrogen is placed above alkali metals. |
| 5 |
No distinguishing positions for metals and non-metals. |
5 |
Metals are present at the left hand side of the periodic table whereas non-metals are present at the right hand side. |
