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प्रश्न
Explain why, the properties of elements are repeated after 2, 8, 18 and 32 elements in the periodic table.
उत्तर
The electronic configurations are repeated because 2, 8, 18 and 32 are the maximum number of electrons that can be placed in the four atomic shells, namely, K, L, M and N. The properties of the elements are repeated after 2, 8, 18 and 32 because the electronic configurations of elements are repeated after 2, 8, 18 and 32.
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संबंधित प्रश्न
Define the term : Atomic size
The elements A, B, C, D and E have atomic numbers 9, 11, 17, 12 and 13 respectively. The pair of elements which belongs to the same group of the periodic table is:
(a) A and B
(b) B and D
(c) A and C
(d) D and E
An element X belong to 4th period and 17th group, state.
no of valence electrons in it
An element X belong to 3rd periods and group II of the periodic table state:
name of the element,
Explain
Size of atom changes when it loses or gain electron
Name the elements in period 1.
What is meant by a Group in the Periodic Table?
Fill in the blanks from the words A to F given below’.
A: Decreases
B: Increases
C: Remains same
D: Increases by one
E: Electropositive
F: Electronegative
Across a period from left to right in the Modern Periodic Table.
No. of electron shells _________; No. of valence electrons __________: Electronegativity increases Character of elements changes from electropositive to ________.
Complete the table pertaining to the following elements given in Column I.
| Column I Elements | Atomic Number | Electronic Configuration | Underline the element present in that group |
| 1. Hydrogen | 1 | ______ | Be/Na/Ca |
| 2. Carbon | 6 | ______, ______ | N/P/Si |
| 3. Nitrogen | 7 | _______, ______ | C/P/S |
| 4. Oxygen | 8 | _______, ______ | N/S/Cl |
| 5. Sulphur | 16 | _____, ______, _______ | O/N/F |
| 6. Chlorine | 17 | _____, ______, ______ | I/O/S |
There are three elements E, F, G with atomic numbers 19, 8 and 17 respectively.
Classify the above elements as metals and non-metals.
