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प्रश्न
From the standpoint of atomic structure, what determines which elements will be the first and which the last in a period of the periodic table?
उत्तर
- The periodic table is based on the atomic number of an element.
- Furthermore, the valence electrons determine their position in the group.
- Elements with one valence electron are classified as the first group, elements with two valence electrons as the second group, and vice versa.
- An element with 8 valence electrons belongs to the Periodic Table's last group (18th group) (excluding He).
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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.
How were the positions of cobalt and nickel resolved in the modern periodic table?
Which element has the electronic configuration 2, 8, 2?
How does the chemical reactivity of the halogens vary on going in group 17 of 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 two elements in halogens.
Name the cation and the anion in the salt – calcium sulphate
Compare Modern Periodic Law with Mendeleev's Periodic Law.
A part of modern periodic table is given below. On its basis, answer the following questions:
| Group No. → | 1 | 2 | 13 | 14 | 15 | 16 | 17 | 18 |
| Period ↓ | ||||||||
| 2 | A | B | ||||||
| 3 | E | D | F | C |
Write the molecular formula of the compound formed by the combination:
E and B
An element has 2 electrons in its N shell.
State its position in periodic table.
