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Question
Name the elements in the correct order of their increasing atomic numbers present in the first, second, and third short periods of the periodic table.
State which of the elements are –
- metallic
- non-metallic
- noble gases
in each of the periods 2 and 3.
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Solution
Names of elements of:
| Period first | Hydrogen | Helium |
| H | He |
| Period – 2 | Li | Be | B | C | N | O | F | Ne |
| Lithium | Beryllium | Boron | Carbon | Nitrogen | Oxygen | Fluorine | Neon |
| Period – 3 | Na | Mg | Al | Si | P | S | Cl | Ar |
| Sodium | Magnesium | Alummium | Silicon | Phosphorus | Sulphur | Chlorine | Argo |
- Metals: Li, Be, Na, Mg, Al
- Non-metals: C, N, O, F, P, S, Cl
- Noble – gases: Ne, Ar
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