Newlands Law of Octaves

The law of octaves, proposed by English chemist J.A.R. Newlands in 1865, marked one of the earliest recognitions of periodicity in elemental properties, foreshadowing the development of the periodic law. Newlands noted that as elements were arranged by increasing atomic masses, every eighth element exhibited striking similarities akin to the repetition of musical notes (do, re, mi, etc.). He termed this recurring pattern the law of octaves.

Döbereiner's work inspired chemists to relate elements' properties to their atomic masses. In 1866, John Newlands arranged known elements by increasing atomic masses, starting with hydrogen and ending with thorium. He observed that every eighth element had similar properties to the first, likening it to musical octaves, thus termed the 'Law of Octaves,' or Newlands' Law of Octaves. 

1.0What is Newlands’ Law of Octaves?

Newlands organized elements based on increasing atomic masses and noted that every eighth element displayed similarities to the first element, akin to musical octaves.

• At that time, inert gases were not known.
• The properties of Li are similar to those of the 8th element, Na, and the properties of Be are identical to those of Mg, and so on.
•  For instance, lithium and sodium exhibit similar properties, with sodium being the eighth element after lithium. Likewise, beryllium and magnesium showed resemblances.
• Chlorine is the eighth element after Fluorine. The chemical properties of Fluorine and Chlorine are identical.

2.0Example Of Newlands’ Octaves

3.0Advantages of Newlands’ Law of Octaves

• Systematically categorizes elements with similar properties into groups.
• Pioneered using atomic weight for periodic classification, linking element properties to atomic masses.
• Particularly effective for lighter elements, e.g., correctly grouped Lithium, Sodium, and Potassium.

4.0Limitations of Newlands’ Law of Octaves

• Newland's arrangement only extended to calcium among the 56 known elements of his time.
• Beyond calcium, the pattern of every eighth element sharing similar properties did not persist.
• With the discovery of more elements post-Newland's time, the scope of his arrangement needed to be updated.
• To fit all known elements into his system, Newlands had to place some aspects in positions where their properties did not align with neighboring elements.
• For instance, iron, with properties resembling cobalt and nickel, was positioned distantly from them.
• The absence of noble gases from the periodic table also stemmed from their later discovery.