1. The maximum number of electrons that can occupy K and L-shells of an atom are 2 and 8 respectively. Therefore, if K and L-shells of an atom are full, then the total number of electrons in the atom would be (2 + 8) = 10 electrons. For more answers visit to website: https://www.tiwariacademy.com/ncertRead more

    The maximum number of electrons that can occupy K and L-shells of an atom are 2 and 8
    respectively. Therefore, if K and L-shells of an atom are full, then the total number of electrons in
    the atom would be (2 + 8) = 10 electrons.

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  2. The total number of electrons in a carbon atom is 6. The distribution of electrons in carbon atom is given by: First orbit or K-shell = 2 electrons Second orbit or L-shell = 4 electrons Or, we can write the distribution of electrons in a carbon atom as 2, 4. The total number of electrons in a sodiumRead more

    The total number of electrons in a carbon atom is 6. The distribution of electrons in carbon atom
    is given by:
    First orbit or K-shell = 2 electrons
    Second orbit or L-shell = 4 electrons
    Or,
    we can write the distribution of electrons in a carbon atom as 2, 4.
    The total number of electrons in a sodium atom is 11. The distribution of electrons in sodium atom
    is given by:
    First orbit or K-shell = 2 electrons
    Second orbit or L-shell = 8 electrons
    Third orbit or M-shell = 1 electron
    Or,
    we can write distribution of electrons in a sodium atom as 2, 8, 1.

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  3. Helium atom has two neutrons. The mass of an atom is the sum of the masses of protons and neutrons present in its nucleus. Since helium atom has two protons, mass contributed by the two protons is (2 × 1) u = 2 u. Then, the remaining mass (4 − 2) u = 2 u is contributed by 2u /1u = 2 neutrons. For moRead more

    Helium atom has two neutrons. The mass of an atom is the sum of the masses of protons and
    neutrons present in its nucleus.
    Since helium atom has two protons, mass contributed by the two protons is (2 × 1) u = 2 u.
    Then, the remaining mass (4 − 2) u = 2 u is contributed by 2u /1u = 2 neutrons.

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  4. The three sub-atomic particles of an atom are: (i) Protons (ii) Electrons, and (iii) Neutrons For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/

    The three sub-atomic particles of an atom are:
    (i) Protons
    (ii) Electrons, and
    (iii) Neutrons

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  5. If the α-scattering experiment is carried out using a foil of a metal rather than gold, there would be no change in the observation. In the α-scattering experiment, a gold foil was taken because gold is malleable and a thin foil of gold can be easily made. It is difficult to make such foils from othRead more

    If the α-scattering experiment is carried out using a foil of a metal rather than gold, there would be no change in the observation. In the α-scattering experiment, a gold foil was taken because gold is malleable and a thin foil of gold can be easily made. It is difficult to make such foils from other metals.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/

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