In Newlands’ Octaves, lithium (Li) and sodium (Na) were observed to have similar properties, as they fall in the same group according to the octaves.
He found that every eighth element had properties similar to that of the first. He compared this to the octaves found in music.
Therefore, he called it the 'Law of Octaves'. According to the Newlands Octaves, the properties of Lithium and Sodium were found to be the same.