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प्रश्न
Write the merits of the modern periodic table over Mendeleev’s Periodic table
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उत्तर
1) Elements are arranged on the basis of increasing atomic number which is more fundamental.
2) Isotopes of an element can be placed along with parent element.
3) It explains periodicity of properties of elements configuration.
4) Lanthanides and actinides are placed separately.
5) Anomalous pairs of elements like Ar and K having same atomic mass could be justified
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संबंधित प्रश्न
Write the names given to the vertical columns and horizontal rows in the Modern Periodic Table. How does the metallic character of elements vary on moving down a vertical column? How does the size of atomic radius vary on moving left to right in a horizontal row? Give reason in support of your answer in the above two cases.
How many rows and columns are there in the Modem Periodic Table?
Why do all the elements of the same group have similar properties?
Give two example of group 17 elements.
What is the significance of atomic number in the modern classification of elements? Explain with the help of an example.
On which side of the periodic table will you find non-metals?
The atomic numbers of four elements P, Q, R and S are 6, 8, 14 and 16 respectively. Out of these, the element known as metalloid is:
(a) P
(b) Q
(c) R
(d) S
Which of the following statement is correct in regard to the classification of elements?
(a) Elements in modern periodic table are arranged on the basis of increasing atomic masses.
(b) Elements in Mendeleev's periodic table are arranged on the basis of increasing atomic numbers.
(c) In modern periodic table, the element nickel of lower atomic mass is kept before the element cobalt of higher atomic mass.
(d) In modern periodic table, the isotopes of chlorine having different atomic masses are kept in the same group.
Consider the following elements:
Na, Ca, Al, K, Mg, Li
Which of these elements belong to the same period of the periodic table?
What is the major characteristic of the first elements in the periods of the periodic table? What is the general name of such elements?
Explain why All the elements of a period have different chemical properties.
State how the valency of elements varies in a group of the periodic table?
What happens to the number of valence electrons in the atoms of elements as we go down in a group of the periodic table?
What is the number of elements is 1st period the modern periodic table?
What is a group in the periodic table?
The elements A, B, C and D belong to groups 1, 2, 14 and 17 respectively of the periodic table. Which of the following pairs of elements would produce a covalent bond?
(i) A and D
(ii) C and D
(iii) A and B
(iv) B and C
(v) A and C
An element barium has atomic number 56. Look up its position in the periodic table and answer the following question.
What will be the formula of its phosphate?
What is meant in the periodic table by a period?
Name an element of group 18 which can form compounds.
Give the symbol and valency of the following element and radical.
Aluminium
Give the symbol and valency of the following element and radical.
Oxygen [Oxide]
State what is meant by the term chemical formula.
Give the chemical formula of calcium phosphate
What are the elements.
The d-block elements are called as _______ elements.
The modern periodic table shows the molecular masses of the elements in each frame.
To the left of the zig-zag line in the periodic table are the metal elements.
In the modern periodic table, the positions of 1 to 20 elements are shown here. Identify the elements A and B. Write their atomic number.
Element ‘X’ forms a chloride with the formula XCl2, which is solid with a high melting point. X would most likely be in the same group of the periodic table as: ______
Which of the following is the outermost shell for elements of period 2?
“Hydrogen occupies a unique position in Modern Periodic Table”. Justify the statement.
Choose an element from period 3 of modern periodic table that matches the description given below in instance. Give a reason for your choice.
It has variable valency and is a member of the Oxygen family (group 16).
______ group elements are called alkaline earth metals.
Spot the error:
The elements of group 13 are called the carbon family.
An element has the atomic number 12.
- Write the electric configuration.
- To which group and period does it belong.
What is the general name of the last elements of the Periodic Table?
Name the following metal:
A metal present in period 3, group 1 of the periodic table.
A group of elements in the periodic table is given below (Boron is the first member of the group and Thallium is the last).
Boron, Aluminium, Gallium, Indium, Thallium
Answer the following question in relation to the above group of elements:
If the electronic configuration of aluminium is 2, 8, 3, how many electrons are there in the outer shell of thallium?
