Question

How Mendeleev’s periodic table differs from Moseley’s

Answer 1

Explanation: Mendeleev’s table listed the elements by arranging them in order of increasing atomic mass. In the early 1900s Henry Moseley, a British physicist, devised a new technique of determining the number of protons in each atom, called its atomic number. He determined the unknown atomic numbers of many elements and rearranged the periodic table in order of atomic number. His results led to more predictions of new elements that were later found.

Answer 2

Moseley didn't develop a Periodic Table. Mendeleev's Periodic Table placed the elements in order of increasing atomic mass, but there were some anomalies. Iodine (126.9 u) had a lower atomic mass than tellurium (127.6 u), and nickel (58.6 u) had a lower atomic mass than cobalt (58.9 u). Moseley showed that these anomalies vanished if the atoms were arranged in order of increasing atomic number. Thus, 52-Te comes before 53-I, and 27-Co comes before 28-Ni. Periodic Tables ever since then have listed the elements in order of atomic number.