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प्रश्न
State how electrons are distributed in an atom. Explain in brief the rules which govern their distribution.
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उत्तर
(a) Electrons revolve around the nucleus in imaginary paths called shells or orbits. Shells start from the nucleus to outwards.
Rules: The maximum number of electrons in a shell is given by 2n2. Where n is the number of shell i.e. 1st shell can have a maximum of 2 electrons.
2n2 = 2(1)2 = 2 × 1 = 2
2nd shell can have maximum of 8 electrons
2n2 = 2(2)2 = 2 × 4 = 8
3rd shell can have maximum of 18 electrons
2n2 = 2 (3)2 = 2 × 9 = 18 and so on….
(b) Outer most orbit cannot have more than 8 electrons and 18 in penultimate orbit.
(c) A new shell cannot start until previous is filled completely.
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संबंधित प्रश्न
Fill in the blank
The outermost shell of an atom is known as............................
Give the following a suitable word/phrase.
Protons and neutrons present in the nucleus.
FILL IN THE BLANK
In an atom, the last shell containing electrons is called its..................shell.
Draw the electronic configuration of the following elements clearly stating the number of neutrons and protons in their nucleus.
a. Beryllium b. Silicon
c. Chlorine d. Aluminium
e. Nitrogen
State whether the following statement is true or false :
The anode rays obtained from all the gases consist of positively charged particles called protons.
Explain how the modern atomic theory contradicted Dalton’s atomic theory.
With reference to the discovery of the structure of an atom, explain in brief – William Crookes experiment for the discovery of cathode rays, followed by – J.J. Thomsons experiment pertaining to the constituents of the cathode rays. State which sub-atomic particle was discovered from his experiment.
Draw a neat labelled diagram representing an atom. Name the three sub-atomic particles in the atom and represent them symbolically showing the mass and charge of each. State where the sub-atomic particles are present in the atom.
Select the correct answer from the choice in the bracket to complete the sentence:
An element ‘X’ has six electrons in its outer or valence shell. Its valency is __________.
Select the correct answer from the choice in the bracket to complete the sentence:
A ________ is a sub-atomic particle with no charge and unit mass.
