Which of the following is not a merit of Mendeleevs periodic table?a)H...
Merits of Mendeleev's periodic table:
1) It helped in correcting the atomic masses of some of the elements e.g. beryllium was corrected from 13.5 to 9. Similarly, indium, gold, platinum etc.
2) He predicted the properties of some undiscovered elements and left gaps for them e.g. Eka-boron, eka-aluminum and eka-silicon names were given for scandium, gallium, and germanium (not discovered at the time of Mendeleev).
3) He framed the periodic table with vertical and horizontal columns and gave shape to it.
4) Isotopes are the atoms of the same element having different atomic masses. Therefore, according to Mendeleev’s classification, these should be placed at different places depending upon their atomic masses. For example, hydrogen isotopes with atomic masses 1,2 and 3 should be placed at three places. However, isotopes have not been given separate places in the periodic table because of their similar properties.
Hence, option DD is correct.
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Which of the following is not a merit of Mendeleevs periodic table?a)H...
As mendleev classified elements on the basis of their chemical properties which generally depends on the number of electron . Meanwhile isotope have same number of electron and henceforth shows similar chemical properties and therefore not classified separately in periodic table.
Which of the following is not a merit of Mendeleevs periodic table?a)H...
Mendeleev's periodic table is a significant contribution to the field of chemistry. It organized the known elements in a systematic manner, allowing for the prediction of the properties of undiscovered elements. However, there are certain merits of Mendeleev's periodic table that are not present in option A:
• Separate places for isotopes: Mendeleev's periodic table did not provide separate places for isotopes. Isotopes are atoms of the same element with different numbers of neutrons. They have the same atomic number but different atomic masses. This concept was not fully understood during Mendeleev's time, so he did not include separate places for isotopes in his periodic table.
• Framing the periodic table: Mendeleev did indeed frame the periodic table with vertical and horizontal columns, giving shape to it. This arrangement allowed for the elements to be organized based on their atomic number, atomic mass, and chemical properties. The periodic table's structure is a fundamental aspect of its organization and utility.
• Prediction of undiscovered elements: One of the remarkable aspects of Mendeleev's periodic table is that he predicted the properties of some undiscovered elements and left gaps for them in the table. He noticed that certain elements were missing and predicted their existence based on the patterns and trends he observed. This was a significant achievement as it demonstrated the power of the periodic table as a predictive tool.
• Correcting atomic masses: Another merit of Mendeleev's periodic table is that it helped in correcting the atomic masses of some elements. Mendeleev arranged the elements not only based on their atomic masses but also their chemical properties. In doing so, he noticed inconsistencies in the atomic masses of certain elements and proposed corrections to these values. This contributed to the refinement and accuracy of atomic mass measurements.
In conclusion, option A is not a merit of Mendeleev's periodic table as it did not provide separate places for isotopes. However, it is important to recognize the other merits of his periodic table, including its structure, the prediction of undiscovered elements, and the correction of atomic masses.
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