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प्रश्न
Write a short note.
Structure of the modern periodic table.
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उत्तर
Structure of the modern periodic table:
Periodic Table: It is the table of chemical elements arranged in order of atomic number such that elements with similar atomic structure appear in the vertical columns. The Modern periodic law states that The chemical and physical properties of elements are a periodic function of their atomic numbers. The modern periodic table is based on modern periodic law.
Groups: There are 18 vertical columns in the periodic table. Each column is called a group. All elements in a group have similar chemical and physical properties because they have the same number of valence electrons.
Periods: In periodic table elements are arranged in a series of rows. Elements of the same period have the same number of electron shells.
Blocks: The table is divided into four blocks: s-block, p-block, d-block, and f-block, based on the type of orbital being filled. s- and p-blocks are called representative elements, d-block are transition metals, and f-block are inner transition elements (lanthanides and actinides).
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संबंधित प्रश्न
In the Modern Periodic Table, which are the metals among the first ten elements?
How many rows and columns are there in the Modem Periodic Table?
Is it possible to have an element having atomic number 1.5 placed between hydrogen and helium?
How does the chemical reactivity of the halogens vary on going in group 17 of the periodic table?
Explain why All the elements of a group have similar chemical properties.
Explain why All the elements of a period have different chemical properties.
State the term
The tabular arrangement of elements in horizontal rows and vertical columns _________
Name the scientist who stated the modern periodic law.
Name two elements in Inert gas.
Name two elements in each case: Lanthanides
Name the type of elements which have outermost shell incomplete.
An element barium has the atomic number 56. Look up its position in the periodic table and answer the following question.
Is it larger or smaller than caesium (Cs)?
How will the tendency to gain electrons change as we go from left to right across a period? Why?
State the modern periodic law.
Answer the following question.
Define the atomic size. Give its unit of measurement. In the modern periodic table what trend is observed in the atomic radius in a group and a period and why is it so?
Give the symbol and valency of the following element and radical.
Sodium
Give the symbol and valency of the following element and radical.
Hydrogen
Give the symbol and valency of the following element and radical.
Bicarbonate
Give the symbol and valency of the following element and radical.
Nitrate
Give the symbol and valency of the following element and radical.
Sulphate
State what is meant by the term chemical formula.
Give the chemical formula of carbonic acid
Compare Modern Periodic Law with Mendeleev's Periodic Law.
The modern periodic table shows the molecular masses of the elements in each frame.
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: ______
The element with atomic number 14 is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?
The amount of energy released when one or more electrons is added to the neutral atom is ______
Which of the following statements about the Modern Periodic Table is correct:
Which of the given elements A, B, C, D and E with atomic number 2, 3, 7, 10 and 30 respectively belong to the same period?
The elements A, B, C, D and E have atomic number 9, 11, 17, 12 and 13 respectively. Which pair of elements belong to the same group?
Arrange the following elements in the increasing order of their metallic character
| Mg, | Ca, | K, | Ge, | Ga |
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?
1H2 is an isotope of hydrogen. In the modern Periodic Table it will ______.
Name the metalloids in the first twenty elements.
Answer the following in respect of element \[\ce{_16^32S}\].
Give its electronic configuration.
Give reason for the following:
Inert gases do not form ion.
