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प्रश्न
State the main helpful features of the long form of the periodic table.
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उत्तर
Long-form of the periodic table has 7 periods horizontal rows and 18 groups vertical columns and properties show regular gradations in periods and also in groups, i.e.
| Electronegativity | → | Increases in a period |
| ↓ | decreases in a group | |
| Non-metallic character | → | Increases in a period |
| ↓ | decreases in a group | |
| Size of an atom | → | decreases in a period |
| ↓ | Increases in a group |
and so on.
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संबंधित प्रश्न
What is meant in the periodic table by a group?
How many electrons do inert gases have in their valence shells?
Comment on the (i) reactivity (ii) colour (iii) physical state of group 17 elements.
Name the gas used in:
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Give reason:
Alkali and alkaline earth metal compounds usually form electrovalent compounds.
Write a short note on the following type of element –
alkali metals
Name or state following with reference to the element of the first three periods of the periodic table.
An alkaline earth metal in period 3.
Give a reason for the following:
Group 1 [I – A] elements are called alkali metals.
State the following:
The group which contains highly reactive electronegative non-metals including chlorine.
Match the elements of List – I with their type from List – II.
| List – I | List – II |
| 1. Highly reactive, univalent metals | A: Halogens |
| 2. Highly reactive, univalent non-metals | B: Transition elements |
| 3. Unreactive, inert elements | C: Alkali metals |
| 4. Elements of group 3 to 12 [IB to VII B and VIII] | D: Lanthanide series |
| 5. Radioactive elements | E: Noble gases |
| F: Actinide series |
