Atomic Structure · Chemistry · COMEDK

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MCQ (Single Correct Answer)

1
The number of electrons with azimuthal quantum numbers $l=1$ and $l=2$ for Cr in the ground state electronic configurations are respectively. [Given: $\mathrm{Cr}(\mathrm{Z}=24)$ ]
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2
The ratio of the difference between the radii of $3^{\text {rd }}$ and $4^{\text {th }}$ orbits of the $\mathrm{He}^{+}$and those of $\mathrm{Li}^{2+}$ is:
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3
Two subatomic particles 1 and 2, with the same kinetic energies have their de- Broglie wavelengths as $\lambda_1 \& \lambda_2$ and masses as 3 m and 6 m respectively. Determine the ratio $\lambda_1: \lambda_2$.
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4
A certain orbital having 2 angular nodes and no radial nodes is:
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5
A certain gas absorbs photon of wavelength $4.0 \times 10^{-7} \mathrm{~m}$ and emits radiation at two wavelengths. If one of the emissions occurs at $7.5 \times 10^{-7} \mathrm{~m}$, what is the wavelength at which the second emission occurs?
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6

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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7
What are the Principal & Azimuthal quantum number values of the valence electrons in tripositive Lutetium?

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8

The correct sequence of filling of electrons in $$n=6$$ is:

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9

The ratio of the first three radii of Bohr's atom is:

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10

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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11

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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12

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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13

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

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14

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

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15

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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16

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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17

Minimum number of nodes are present in

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18

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

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19

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

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20

The Paschen series of hydrogen spectrum lies in which region?

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21

The total number of nodes are given by

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22

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

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23

The Lyman series of hydrogen spectrum lies in which region

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24

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)

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25

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

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