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प्रश्न
How many elements were known at the time of Mendeleev's classification of elements?
उत्तर
Only 63 elements were discovered at the time of Mendeleev's classification of elements.
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संबंधित प्रश्न
Why did Mendel choose garden pea for his experiments? Write two reasons.
Write the merits of Mendeleev’s periodic table.
Use Mendeleev's Periodic Table to predict the formula of hydrides of carbon and silicon.
Use Mendeleev's Periodic Table to predict the formula of oxides of potassium, aluminum, and barium.
How did Mendeleev arrange the elements in the periodic table?
Write scientific reason.
There was no definitive place for isotope in Mendeleev’s periodic table.
On moving from left to right in a period in the periodic table, the size of the atom.
Properties of the elements are given below. Where would you locate the following elements in the periodic table?
- A soft metal stored under kerosene
- An element with variable (more than one) valency stored under water.
- An element which is tetravalent and forms the basis of organic chemistry
- An element which is an inert gas with atomic number 2
- An element whose thin oxide layer is used to make other elements corrosion resistant by the process of “ anodising”
Mendeléev predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminium.
- Name the elements which have taken the place of these elements
- Mention the group and the period of these elements in the Modern Periodic Table.
- Classify these elements as metals, non-metals or metalloids
- How many valence electrons are present in each one of them?
List the features of Mendeleev’s Periodic Table.
