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प्रश्न
How many atoms are there in exactly 12 g of carbon-12 element ? (C = 12 u)
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उत्तर
6.022 × 1023 atoms are present in 12g of carbon-12 element.
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संबंधित प्रश्न
Why is it not possible to see an atom with naked eyes?
TRUE \ FALSE
Elements having a tendency to accept electrons are called metals
TRUE \ FALSE
Cathode rays are a stream of fast moving particles that travel in random directions.
ANSWER IN DETAIL
State the postulates of the Dalton’s atomic theory.
State Dalton’s atomic theory.
Fill in the blank
If an atom loses an electron, it acquires ______ a charge.
Fill in the blank
A deficiency of electrons produces a ________ charge.
What is the usual symbol for (a) and electron (b) a proton, and (c) a neutron?
Why is it not possible to see an atom even with the most powerful microscope ?
Fill in the following blanks with suitable words :
In water, the proportion of oxygen and hydrogen is .............. by mass.
How many times is a proton heavier than an electron?
Calculate the number of moles in 12.044 × 1025 atoms of phosphorus.
Give brief information of three subatomic particles with reference to electrical charge, mass and location.
Draw diagrams representing the atomic structures of the following:
- Sodium atom
- Chlorine ion
- Carbon atom
- Oxygen ion
Elements X and Y have 1 and 7 electrons in their outermost shell respectively.
Which element will gain electron?
The electronic structure [configuration] of fluorine can be written as 2, 7. In a similar way give the electronic configuration of phosphorus
Define the following term with an example.
Element
Project.
To have an idea of what atoms are, students can be asked to construct atoms using pipe cleaners (thin metal wires-electron shells), pompoms (balls-different colours for protons and neutrons) and beads (electrons). Students will love and enjoy putting them together and they look great hanging from the ceiling in the classroom.
Give the salient features of “Modern atomic theory”.
