Up to which element, the law of Octaves was found to be applicable?

Up to the calcium element, the law of octaves was found to be applicable.
It was discovered that the law of octaves held true up to the element calcium (Ca). In 1866, John Newlands, an English scientist, arranged the known elements in the order of increasing atomic masses. He started with the element having the lowest atomic mass (hydrogen) and ended with thorium which was the 56th element.
The law of Octaves is applicable up to Calcium. 

The law was applicable for lighter particles only up to 40 u. After Calcium, the property of every eight elements does not resemble that of the first.