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प्रश्न
State the periodic law on which Mendeleev's periodic table table was based. Why and how was this periodic law changed?
उत्तर
According to Mendeleev's periodic law, the properties of elements are a periodic function of their atomic masses. This means that when elements are arranged in an increasing order of their atomic masses, the elements with similar properties repeat at regular periods.
However, Henry Moseley, a scientist, showed that the atomic number of an element is a more fundamental property and a better basis to classify elements than the atomic mass. The atomic number increases consistently by 1, from one element to the next, whereas the atomic mass does not change regularly. Also, the atomic number of an element does not change and remains fixed. This led to a change in Mendeleev's periodic law.
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संबंधित प्रश्न
Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic Table.
What was the Mendeleev's basis for the classification of elements?
The three elements predicted by Mendeleev from the gaps in his periodic table were known as eka-boron, eka-aluminimum and eka-silicon. What names were given to these elements when they were discovered later on?
What name were given by Mendeleev to the then undiscovered element gallium?
In Mendeleev's periodic table, why was there no mention of noble gases like helium, neon and argon?
Why could no fixed position be given to hydrogen in Mendeleev's periodic table?
Find the odd one out and give its explanation.
Find the odd one out and give its explanation.
Match the columns.
| Column A | Column B |
| 1) Triads | a) Mendeleev |
| 2) Octave | b) Dobereiner |
| 3) Atomic number | c) Thomson |
| 4) Atomic mass number | d) Moseley |
| e) Newland |
Describe the merits of Mendeleev’s periodic table?
