Question

Which of the following did Moseley believe?

A. The elements should be arranged based upon current knowledge of electrons
B. The elements should be arranged based upon the number of neutrons
C. Periodic table should be organized based upon atomic number
D. The periodic table should be organized based upon chemical properties

Answer 1

The answer is C.

Step-by-step explanation

Before Moseley's discovery, the atomic numbers (or elemental number) of an element had been thought of as a semi-arbitrary sequential number, based on the sequence of atomic masses.

The atomic mass of cobalt is slightly larger than that of nickel, which would have placed them in backwards order if they had been placed in the Periodic Table blindly according to atomic mass.

Moseley's experiments in X-ray spectroscopy showed directly from their physics that cobalt and nickel have the different atomic numbers, 27 and 28, and that they are placed in the Periodic Table correctly by Moseley's objective measurements of their atomic numbers.