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प्रश्न
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.
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उत्तर
- Element A is lithium (Li).
Element B is neon (Ne). - Atomic number of element A is 3.
Atomic number of element B is 10.
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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.
What is periodicity in properties of elements with reference to the Modern Periodic Table?
State modern periodic law.
Fill in the following blank with suitable word:
The basis for modern periodic table is ...............
How were the positions of cobalt and nickel resolved in the modern periodic table?
Which element has two shells, both of which are completely filled with electrons?
Give alongside is a part of the periodic table :
As we move horizontally from left to right:
| Li | Be | B | C | N | O | F | |
| Na | Mg | Al | Si | P | S | Cl |
(i) What happens to the metallic character of the elements?
(ii) What happens to the atomic size?
How does the chemical reactivity of alkali metals vary on going in group 1 of the periodic table?
What is the number of valence electrons in the atoms of first elements in a period?
On the basis of electronic configuration, how will you identify the first element of a period?
What is the usual number of valence electrons and valency of group 18 elements 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?
Explain why, the first period of the periodic table has only two elements whereas second period has eight elements
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.
What are the groups in a periodic table? Give two characteristics of each.
Give the group number of following elements present in periodic table
Name two elements in Alkaline earth metals.
Name the type of elements which have one electron short of octet.
Arrange the elements of second and third periods in increasing order of their atomic size.
Third Period.
Write the number of protons, neutrons and electronic configuration of \[\ce{_19^39K, _15^31P}\]. Also state their position in periodic table.
Answer the following in respect of element `31/15 P`
Give its electronic configuration
Write a short note.
Position of isotopes in the Mendeleev’s and the modern periodic table.
State the modern periodic law.
Define the atomic size.
Give the symbol and valency of the following element and radical.
Sulphur [Sulphide]
Give the symbol and valency of the following element and radical.
Bicarbonate
Give the symbol and valency of the following element and radical.
Bisulphate
The groups 1 and 2 constitute the _______ block.
Find the odd one out and give its explanation.
The modern periodic table has 1 to 7 periods.
The modern periodic table shows the molecular masses of the elements in each frame.
Explain structure of modern periodic table in short.
The arrangement of elements in the Modem Periodic Table is based on their ______
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 elements does not lose an electron easily?
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
Answer the following in respect of element \[\ce{_16^32S}\].
Give its formula with hydrogen.
