Newlands Octaves start with _____ and end with ______ , respectively.

Correct option is B

The correct answer is (b) H; Th

Explanation:
• John Newlands proposed the Law of Octaves in 1865, which arranged elements in increasing order of their atomic masses.
• He observed that every eighth element showed properties similar to the first, just like the eighth note in a musical octave.
• His classification began with Hydrogen (H) and ended with Thorium (Th).

Information Booster:
• Newlands’ Octaves included 56 elements known at that time.
• It was the first attempt to relate an element’s properties to its atomic mass.
• The law worked well only up to Calcium (Ca) and failed for heavier elements.
• Later, Mendeleev’s Periodic Table (1869) improved upon Newlands’ model.
• The concept of periodicity introduced by Newlands laid the foundation for the modern periodic table.

Additional Knowledge:
• The Law of Octaves compared the periodicity of elements to the repetition of musical notes.
• It failed because new elements discovered later did not fit the pattern.
• Modern classification is based on atomic number, not atomic mass.
• The modern periodic law was proposed by Henry Moseley in 1913.
• Newlands’ work was later recognized as a pioneering effort in establishing chemical periodicity.