Which discovery caused a revision in the periodic law as stated by Mendeleev ?
Correct answer: B. Atomic number by Moseley
- A. Location of nucleus by Rutherford
- B. Atomic number by Moseley
- C. X-rays by Roentgen
- D. Natural radioactivity by Henry Bacquerel.
Explanation
Moseley showed that elements should be arranged by increasing atomic number rather than atomic mass, leading to the modern periodic law and correcting anomalies in Mendeleev's table. The likely distractor is a, Rutherford's nucleus, because nuclear structure is related to atomic identity, but Moseley's measurements directly established atomic number as the basis of order.
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About Periodic Properties and Trends
Periodic properties arise from electron configuration and effective nuclear charge, producing trends in atomic and ionic radius, ionization energy, electron affinity, electronegativity, metallic character and reactivity. Comparisons run across periods and down groups, with attention to common exceptions. The topic also relates these trends to the behavior of s-block and p-block elements.
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