SSC
CHEMISTRY
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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H2O
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H
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NaCl
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CaCO3
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Detailed explanation-1: -Hydrogen is represented by the symbol H.
Detailed explanation-2: -Elements are represented by a chemical symbol, with the atomic number and mass number sometimes affixed as indicated below. The mass number is the sum of the numbers of neutrons and protons in the nucleus.
Detailed explanation-3: -H2 is a molecule which forms when two hydrogen atoms bond together and become a hydrogen molecule. H2 is also called molecular hydrogen.
Detailed explanation-4: -Hydrogen, with the formula H2, is an element, not a compound. Compounds can be decomposed into their constituent elements. An example is water being chemically decomposed into its two elements, hydrogen and oxygen, by electrolysis: passing electricity though a water solution.