Atomic Structure · Chemistry · COMEDK

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MCQ (Single Correct Answer)

1

What is the wave number (Units $$\mathrm{cm}^{-1}$$) of the longest wave length transition in the Balmer series of Hydrogen spectrum? $$Z=1 \text { for } H$$

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2
What are the Principal & Azimuthal quantum number values of the valence electrons in tripositive Lutetium?

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3

A statement of Assertion followed by a statement of Reason is given. Choose the correct answer out of the following options.

Assertion : Energy of $$2 \mathrm{~s}$$ orbital of Hydrogen is less than the energy of the $$2 \mathrm{~s}$$ orbital of Lithium.

Reason : Energies of orbitals in the same subshell decrease with increase in atomic number.

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4

Given below are 4 subatomic particles travelling with the same velocity "v". Which of them will have the shortest wavelength?

$$[A]=\text { Proton }[B]=\text { Neutron. }[C]=\text { Alpha particle. }[D]=\text { Electron. }$$

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5

The mass number of an element $$\mathrm{X}$$ is 175 with 104 neutrons in its nucleus. Into which one of the following orbitals will the last electron enter?

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6

Bohr's radius of 2 nd orbit of $$\mathrm{Be}^{3+}$$ is equal to that of

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7

The ion that is isoelectronic with $$\mathrm{CO}$$ is

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8

A proton having mass equal to $$1.66 \times 10^{-27} \mathrm{~kg}$$ is accelerated to one tenth of the velocity of light. If its velocity can be measured to an accuracy of $$\pm 2 \%$$, what would be the uncertainty in its position?

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9

The energy of an electron in the ground state of Hydrogen atom is $$-2.18 \times 10^{-18} \mathrm{~J}$$. What would be the energy associated with the second excited state of $$\mathrm{Li}$$ ?

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10

Minimum number of nodes are present in

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11

$$\mathrm{O^{2-},F^-,Mg^{2+},Al^{3+},O_2,F_2}$$. How many of the species given above isoelectronic?

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12

The spectrum of He$$^+$$ is similar to

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13

The Paschen series of hydrogen spectrum lies in which region?

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14

The total number of nodes are given by

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15

Which of the following series of transitions in the spectrum of hydrogen atom fall in visible region?

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16

The Lyman series of hydrogen spectrum lies in which region

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17

A body of mass 10 mg is moving with a velocity of 100 ms$$^{-1}$$. The wavelength of de-Broglie wave associated with it would be

($$h=6.63\times10^{-34}$$ Js)

COMEDK 2020
18

Mg$$^{2+}$$ is isoelectronic with

COMEDK 2020
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