Whose Periodic Law was modified and adopted the Atomic number as the basis of Modern Periodic Table?

The correct answer is Henry Moseley.

Key Points

• Henry Moseley modified Mendeleev's Periodic Law by adopting the atomic number as the basis for the arrangement of elements in the Modern Periodic Table.
• Moseley demonstrated that the properties of elements are periodic functions of their atomic numbers, not their atomic masses.
• His experiments in 1913 using X-ray spectroscopy led to the discovery that each element has a unique number of protons, which defines its atomic number.
• The modern periodic table is based on Moseley's Periodic Law, which corrected anomalies in Mendeleev's arrangement of elements.
• Moseley's work resolved inconsistencies such as the placement of isotopes and the correct ordering of elements like iodine and tellurium.

Additional Information

• Atomic Number:
  • The atomic number is the number of protons in the nucleus of an atom and determines the element's identity.
  • It is denoted by the symbol "Z" and is fundamental to the arrangement of the periodic table.
• Mendeleev's Periodic Law:
  • Dmitri Mendeleev initially arranged elements based on their atomic masses, leaving gaps for undiscovered elements.
  • However, some elements were misplaced due to discrepancies in their properties and atomic mass order.
• X-ray Spectroscopy:
  • Henry Moseley used X-ray spectroscopy to study the frequencies of X-rays emitted by elements, establishing a direct relationship with their atomic numbers.
  • This technique confirmed the periodicity based on atomic number.
• Modern Periodic Table:
  • The modern periodic table is structured based on Moseley's findings, arranging elements in increasing atomic number.
  • It successfully predicts the chemical and physical properties of elements.
• Periodic Trends:
  • Periodic trends such as electronegativity, ionization energy, and atomic radius are better explained using the modern periodic table.
  • These trends are consistent across periods and groups, showcasing the periodic nature of elements.