Advertisements
Advertisements
प्रश्न
Find the correlation:
Mendeleev’s periodic table : atomic mass : : Modern periodic table : _______
Advertisements
उत्तर
Mendeleev’s periodic table : atomic mass : : Modern periodic table : atomic number
Explanation:
Mendeleev organised his periodic table based on the atomic mass of elements. In contrast, the modern periodic table is based on the atomic number (the number of protons), which Henry Moseley demonstrated to be a more fundamental property for predicting periodic trends in chemical behaviour.
APPEARS IN
संबंधित प्रश्न
In the Modern Periodic Table, calcium (atomic number 20) is surrounded by elements with atomic numbers 12, 19, 21, and 38. Which of these have physical and chemical properties resembling calcium?
On which side of the periodic table will you find metals?
What is the name of those elements which divide metals and non-metals in the periodic table?
The atomic particle whose number in the atoms of an element always remains the same and which forms the real basis for the modern classification of elements is:
(a) electron
(b) proton
(c) neutron
(d) meson
Which element has two shells, both of which are completely filled with electrons?
What is the usual number of valence electrons and valency of group 18 elements of the periodic table?
Helium and neon are unreactive gases. What, if anything, do their atoms have in common?
From the standpoint of atomic structure, what determines which element will be the first and which the last in a period 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
Name the scientist who stated the modern periodic law.
Write the number of protons, neutrons and electronic configuration of \[\ce{_19^39K, _15^31P}\]. Also state their position in periodic table.
Name and state the following with reference to the elements of the first three periods of the periodic table.
A covalent compound formed by an element in period 2 and a halogen.
Give the symbol and valency of the following element and radical.
Potassium
Give the symbol and valency of the following element and radical.
Magnesium
Give the symbol and valency of the following element and radical.
Zinc
Give the symbol and valency of the following element and radical.
Chlorine [Chloride]
State the number of elements in Period 1 of the Periodic Table.
State the number of elements in Period 2 of the Periodic Table.
State the number of elements in Period 3 of the Periodic Table.
Compare Modern Periodic Law with Mendeleev's Periodic Law.
The d-block elements are called as ______ elements.
Find the correlation:
Group 1 and 2 : s block : : group 13 and 18 : ______
Right or wrong sentence.
The K and L shells of the elements Na and Mg contain electrons.
Write an explanation.
Period
Distinguish between:
Group 17 - Group 18
Position of A, B and C three elements is given in the table from the modern periodic table. Answer the following questions.
| Periods | Group 2 | Group 17 |
| 2 | ----- | A |
| 3 | B | ----- |
| 4 | ----- | C |
- What is an element metal or nonmetal?
- Which is the outermost orbit of element B?
- Identify C element and it's physical state.
State any five features of modern periodic table.
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: ______
The inert gas which lies in the third period is ______
The three elements A, B and C with similar properties have atomic masses X, Y and Z respectively. The mass of Y is approximately equal to the average mass of X and Z. What is such an arrangement of elements called as? Give one example of such a set of elements.
Compare the radii of two species X and Y. Give reasons for your answer.
- X has 12 protons and 12 electrons
- Y has 12 protons and 10 electrons
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 same valency as Lithium.
______ group elements are called alkaline earth metals.
Give the criteria on the basis of which elements are placed (i) in a group and (ii) in a period in the modern periodic table. The atomic number of an element is 16. According to the criteria, in which group and period it should be placed?
Define groups of modern 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?
