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प्रश्न
Define:- Molecule
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उत्तर
Molecule : Molecule is the smallest unit of a compound (or an element) which always has an independent existance.
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संबंधित प्रश्न
Tick the most appropriate answer.
Who discovered that radioactive rays are given out by uranium?
- Henri Becquerel
- Marie Curie
- Pierre Curie
- Schmidt
TRUE \ FALSE
Elements combine in definite proportions to form compounds.
WRITE SHORT ANSWER
Define an ionic compound.
Write the names of the elements present in the following compound.
Common salt
Give the charge and the mass of an electron, proton and neutron present in an atom ?
An atom has 13 protons and 14 neutrons.
What is the atomic number of the atom ?
A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.
What is such a particle called ?
How is the size of an atom indicated ?
Write the relation between nanometre and metre.
Why is it not possible to see an atom even with the most powerful microscope ?
Define the following term:
Atom
In what respects do the three isotopes of hydrogen differ? Give their structures.
State true or false. If false, correct the statement.
The basic unit of an element is molecule.
Name the sub-atomic particles.
An atom of an element has no electron. Will that atom have any mass or not? Can an atom exist without electron? If so then give example.
Define the following term with an example.
Metal
An element is composed of ______ atoms.
In the nucleus of `""_20"Ca"^40`, there are ______
What is the fundamental particle of an element?
