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प्रश्न
Write scientific reason.
Mendeleev kept vacant places in the periodic table.
उत्तर
- In Mendeleev’s periodic table, the elements are arranged in increasing order of their atomic masses such that chemically similar elements are placed together in a group.
- However, while arranging the elements, Mendeleev kept vacant places in the periodic table for elements not discovered till then.
- Three of these unknown elements were given the names eka-boron, ekaaluminium and eka-silicon from the known neighbours.
- The atomic masses of these elements were indicated as 44, 68 and 72, respectively. He also predicted their properties.
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संबंधित प्रश्न
Use Mendeleev’s Periodic Table to predict the formulae for the oxides of the following elements:
K, C, Al, Si, Ba.
Name three elements that have a single electron in their outermost shells.
Name two elements that have two electrons in their outermost shells.
Name three elements with filled outermost shells.
Element X forms a chloride with the formula XCl2, which is a solid with a high melting point. X would most likely be in the same group of the Periodic Table as
State whether the following statement is true of false:
According to Mendeleev's periodic law, the properties of elements are a periodic function of their atomic numbers.
Name the Russian chemist who said that the properties of elements are a periodic function of their atomic masses.
State Mendeleev's periodic law.
(a) Write its electronic configuration and determine its valency.
(b) Is it more reactive or less reactive than Ca (atomic number 20)? Justify your answer giving reason.
(c) Is it a metal or a non-metal?
(d) Write the formula of its oxide.
Explain in brief how Mendel interpreted his results to show that the traits may be dominant or recessive.
Use Mendeleev's Periodic Table to predict the formula of hydrides of carbon and silicon.
Why did Mendeleev's leave some gaps in his periodic table os elements? Explain your answer with an example.
Name two elements whose atomic weights were corrected on the basis of their positions in Mendeleev's periodic table.
How many elements were known at the time of Mendeleev's classification of elements?
How did Mendeleev arrange the elements in the periodic table?
What was the basis of Mendeleev's classification?
How did Mendeleev's arrangement of elements correlate with the periodicity of the properties of elements?
According to Mendeleev’s periodic law, properties of elements are periodic function of their _______.
At the time of Mendeleev _______ elements were known.
Distinguish between:
Mendeleev’s periodic table - Modern periodic table
At the time of Mendeleev, the number of elements known was ______
The properties of eka-aluminum predicted by Mendeleev are the same as the properties of a later discovered elements: ______
An element has 12 protons. The group and period to which this element belongs is ______
Which of the following oxide is most basic?
Which of the following properties does not match the element of the halogen family?
In Mendeléev’s Periodic Table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the periodic table later
Which of the following statement (s) about the Modern Periodic Table are incorrect
- The elements in the Modern Periodic Table are arranged on the basis of their decreasing atomic number
- The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic masses
- Isotopes are placed in adjoining group (s) in the Periodic Table
- The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic number
On moving from left to right in a period in the periodic table, the size of the atom.
In Mendeléev’s Periodic Table the elements were arranged in the increasing order of their atomic masses. However, cobalt with atomic mass of 58.93 amu was placed before nickel having an atomic mass of 58.71 amu. Give reason for the same.
List the features of Mendeleev’s Periodic Table.
Mendeleev's periodic table was based on ______.
Name the elements whose compounds formed the basis of classification in Mendeleev's periodic table. Why did Mendeleev choose these elements?
How the formulae of these compounds had helped Mendeleev in deciding the position of an element in his periodic table?
