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प्रश्न
Distinguish between:
Group 17 - Group 18
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उत्तर
| Group 17 | Group 18 | |
| 1. | Elements of group 17 are called halogens. | Elements of group 18 are called inert gas elements or noble gases. |
| 2. | They have seven valence electrons. | They have eight valence electrons except helium which contains 2 electrons. |
| 3. | Their valency is 1. | Their valency is zero. |
| 4. | They form diatomic molecules with general formula (X2). | They are monoatomic gases under normal conditions. |
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| Period ↓ | ||||||||
| 2 | A | B | ||||||
| 3 | E | D | F | C |
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