Newlands' Law of Octaves
- Arranged according to the ascending order of the elements' atomic mass.
- Every eight element, starting from a given one, had similar properties as the first one.
However, his classification was not accepted by the scientific community because:
- Newlands' rule did not hold true at all for elements beyond calcium.
- He did not leave blank spaces in his table for undiscovered elements.
Mendeleev's Periodic Table
- Arranged the elements in order of increasing R.A.M.
- He left gaps where necessary to ensure that similar elements were grouped together.
- Vertical columns = groups
- Horizontal columns = periods