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प्रश्न
Give three reasons why – carbon dioxide is considered a compound, while carbon – an element.
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उत्तर
Carbon dioxide (C02) has a formula and properties of C02 to extinguish fire etc. are quite different from the properties it constituents carbon and oxygen. Oxygen (O) and carbon (C) are elements as these are made up of one kind of atoms. Also, carbon is combustible and oxygen is a supporter of combustion
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संबंधित प्रश्न
Write the symbols of helium, silver, krypton, antimony, barium.
What do the following symbol stand for?
2H
How are the elements with variable valency named? Explain with an example.
Give two examples of the following:
Liquid + Liquid mixture:
Match the metallic elements – with their correct symbols Metallic elements
| Metallic elements | Symbol |
| (a) Potassium | (1) Ca |
| (b) Sodium | (2) Zn |
| (c) Calcium | (3) Pb |
| (d) Magnesium | (4) Hg |
| (e) Zinc | (5) Cu |
| (f) Aluminum | (6) Au |
| (g) Iron | (7) K |
| (h) Lead | (8) Fe |
| (i) Copper | (9) Al |
| (j) Mercury | (10) Na |
| (k) Silver | (11) Mg |
| (l) Platinum | (12) Pt |
| (m) Gold | (13) Ag |
Match the symbols of metallic elements – with their correct combining power or capacity.
(a) K
(b) Zn
(c) Al
(d) Na
(e) Ca
Combining power or capacity – A : 3 ; B : 2 ; C : 1. (positive valencies)
State the type of element for the following:
Calcium
State a reason why the symbol of calcium is ‘Ca’ and of copper is ‘Cu’
Certain metal exhibit variable valencies which include valencies: 1+, 2+, 3+, and 4+.
State the variable valency of the following metal.
Iron
write symbol with the variable valency
What does the symbol '(aq.)' present in a chemical equation, mean?
