Question

John Newlands arranged the known elements in a/an ______ order of their atomic _______ .

• A. increasing, masses
• B. decreasing, masses
• C. increasing, numbers
• D. decreasing, numbers

Answer 1

The correct option is A increasing, masses

John Newlands arranged the known elements in increasing order of their atomic masses. He started with the element having the lowest atomic mass ( hydrogen) and ended at thorium which was the ${56}^{th}$ element. He found that every eighth element had properties similar to the first. Some of the elements satisfying this order are arranged as $H,Li,Be,B,C,N,O$.