EVERYDAY SCIENCE

Detailed explanation-1: -All the systems put the elements in order of increasing atomic weight, which is why they cluster in the 1860s. Before that time chemists did not have accurate atomic weights; some were off by a factor of two, being measured as twice as heavy or twice as light as what we now recognize as their true weights.

Detailed explanation-2: -In 1864, with about 50 elements known, the British chemist John Newlands noticed a pattern when he arranged the elements in order of atomic mass, or weight. He found that the properties of the elements seemed to repeat every eighth element. He called this the Law of Octaves, comparing it to musical scales.

Detailed explanation-3: -By the early 1800’s, chemists started organizing elements into groups because; There were so many new elements that had been discovered. The atomic number of an element is the total number of which particles in the nucleus?

Detailed explanation-4: -The earliest attempt to classify the elements was in 1789, when Antoine Lavoisier grouped the elements based on their properties into gases, non-metals, metals and earths.