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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
Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice?
How many rows and columns are there in the modern periodic table?
Fill in the following blank with suitable word:
Group 18 elements are called ...............
What is meant by a period, in a periodic table?
How many periods and groups are there in the long form of periodic table?
Would you place the two isotopes of chlorine, CI-35 and CI-37 in different slots because of their different atomic masses or in the same slot because their chemical properties are the same? Justify your answer.
The three elements having chemical symbols of Si, B and Ge are:
(a) all metals
(b) all non-metals
(c) all metalloids
(d) Si is metalloid, B is metal and Ge is non-metal
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
State how the valency of elements varies in a period of the periodic table?
On the basis of electronic configuration, how will you identify the first element of a period?
Helium and neon are unreactive gases. What, if anything, do their atoms have in common?
In what respects do the properties of group 1 elements differ from those of group 17 elements? Explain with examples by taking one element from each group.
The atomic numbers of the three elements X, Y and Z are 2, 6 and 10 respectively.
(i) Which two elements belong to the same group?
(ii) Which two elements belong to the same period?
Give reasons for your choice.
Consider the following elements:
20Ca, 8O, 18Ar, 16S, 4Be, 2He
Which of the above elements would you expect to be:
(i) very stable?
(ii) in group 2 of the periodic table?
(iii) in group 16 of the periodic table?
Give the group number of following elements present in periodic table
How many groups and periods does the modern periodic table have?
Name two elements in each case:
Actinides
Name the type of elements which have outermost shell incomplete.
Answer the following in respect of element `31/15 P`
Give its electronic configuration
State the modern periodic law.
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.
An element A has 2 electrons in its fourth shell. State its electronic configuration.
Give the symbol and valency of the following element and radical.
Calcium
Give the symbol and valency of the following element and radical.
Bisulphate
Give the chemical formula of sodium hydroxide
Give the chemical formula of sodium sulphite
Give the chemical formula of calcium phosphate
What are the elements.
p-block is composed of groups 1 and 2.
State whether true or false. If false, correct the statement.
Lanthanides and actinides are kept at the bottom of the periodic table because they resemble each other but they do not resemble with any other group elements.
What are groups and periods in the modern periodic table?
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?
Which of the following is the outermost shell for elements of period 2?
Which of the following elements will form an acidic oxide?
Match the atomic number with the following:
A rare gas.
Give reason for the following:
Inert gases do not form ion.
