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प्रश्न
‘The modern periodic table consists of elements arranged according to their increasing atomic numbers’. With reference to elements with atomic numbers 1 to 20 only in the periodic table – differentiate them into – metallic elements, metalloids, non-metals & noble gases.
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उत्तर
Names and symbols of metal, non-metals, metalloids, and noble – gases out of 1st 20 elements.
| Metal | Symbol | Non-metal | Symbol |
| Lithium | Li | Hydrogen | H |
| Beryllium | Be | Carbon | C |
| Sodium | Na | Nitrogen | N |
| Magnesium | Mg | Oxygen | O |
| Aluminium | Al | Fluorine | F |
| Potassium | K | Phosphorus | P |
| Calcium | Ca | Sulphur | S |
| Chlorine | Cl |
| Metalloids | Symbol | Noble gas | Symbol |
| Boron | B | Helium | He |
| Silicon | Si | Neon | Ne |
| Argon | Ar |
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संबंधित प्रश्न
Give one example for the following types of mixtures :
solid-liquid heterogenous mixture.
Mention three gaseous elements and write their molecular formulae
Answer the following question:
Why are copper and aluminium used to make electric wires?
Tick (√) the correct alternative from the choice given for the following statement
The most ductile metal.
Tick (√) the correct alternative from the choice given for the following statement
A gaseous non-metal.
Match the statements in List I – 1 to 10 correct answers in List II-A to J.
| List I | LIst II | ||
| 1 | Fluorine and chlorine | A | Nitrogen |
| 2 | A diatomic molecule | B | Boron |
| 3 | A molecule containing the elements hydrogen and oxygen. | C | Reactants |
| 4 | A metalloid - showing properties of both metals and non-metals. | D | Chemical Formula |
| 5 | The term used for the substances which take part in the chemical reaction | E | Halogens |
| 6 | The term represents a substance by means of symbols. | F | Water |
| 7 | The term used for the substances formed as a result of a chemical reaction | G | Nitric Acid |
| 8 | A compound containing one atom of zinc and two atoms of chlorine. | H | Products |
| 9 | The chemical name for nitrogen monoxide. | I | Phosphorus |
| 10 | A polyatomic molecule. | J | Zinc Chloride |
Give an example of two liquids that form heterogeneous mixtures.
Select the correct answer from the choice given below to complete the sentence :
Compounds are ____________ in nature.
There are ______ number of known elements.
Give an account of elements known to us.
