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Chemistry

Atomic Structure

103 questions · Click an option and press Check Answer to reveal the result

Any f-orbital can accommodate upto;

2 electrons with parallel spin

6 electrons

2 electrons with opposite spin

14 electrons

Which one of the following sets of ions represents the collection of isoelectronic species? (Atomic no. F = 9, Cl = 17, Na = 11, Mg = 12, Al = 13, K = 19, Ca = 20 Sc = 21).

K+ , Ca2+, Sc3+, Cl–

Na+ , Ca2+, Sc3+, F–

K+ , Cl– , Mg2+, Sc3+

Na+ , Mg2+, Al3+, Cl–

Rutherford’s experiment, which established the nuclear model of an atom, used a beam of;

β-particles, which impinged on a metal foil and get absorbed.

γ-rays, which impinged on a metal foil and ejected electron.

Helium atoms, which impinged on a metal foil and got scattered

Helium nuclei, which impinged on a metal foil and got scattered

Which one among the following statements is correct?

An orbital containing an electron having quantum numbers n = 2; l = 0; m = 0 and s = +1/2 is spherical.

The frequency of X-rays is less than that of radio-waves.

All photons have same energy.

As intensity of light increases, its frequency also increases.

Match List-I with List-II. List-I List-II (A) n = 3, l = 0 (I) 3p orbital (B) n = 4, l = 2 (II) 4s orbital (C) n = 4, l = 0 (III) 3s orbital (D) n = 3, l = 1 (IV) 4d orbital Choose the correct answer from the options given below:

A-III, B-II, C-IV, D-I

A-III, B-IV, C-II, D-I

A-III, B-I, C-II, D-IV

A-I, B-IV, C-II, D-III

For a given value of azimuthal quantum number l, the total number of values for the magnetic quantum number m are given by:

l + 1

2l + 1

2l – 1

l + 2

Given below are two statements: Statement I: Kinetic energy of photoelectrons depend upon frequency. Statement II: The e/m ratio of electron is less than proton. In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I is correct, but Statement II is incorrect.

Statement I is incorrect, but Statement II is correct.

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect.

Maximum number of angular nodes are present in

All have the same number of nodes

The ratio of minimum to maximum wavelengths in Balmer series of H-atom is:

5 : 9

5 : 36

1 : 4

3 : 4

Which experiment is responsible for finding out the charge on an electron?

Millikan’s oil drop experiment

Cathode ray discharge tube experiment

Rutherford’s α-rays scattering experiment

Photoelectric experiment

The energy of an electron moving in nth Bohr’s orbit of an element is given by En = –13.6Z²/n² eV/atom. The graph of E vs Z² (keeping “n” constant) will be;

(1)

(2)

(3)

(4)

The number of angular nodes for 4f orbital is:

If an electron has spin quantum number of +1/2 and a magnetic quantum number of –1, then e– may not be present in;

s-orbital

p-orbital

d-orbital

f-orbital

The radiations having minimum wavelength among the following is:

Radiowaves

Microwaves

UV-rays

X-rays

Bohrs theory is not applicable to;

Li2+

He+

the H-atom

The radius of first Bohr's orbit for hydrogen is 0.53 Å. The radius of third Bohr's orbit would be

0.79Å

1.59 Å

3.18 Å

4.77 Å

Which of the following statements is incorrect?

The concepts of "penetration" and "shielding" are important in deciding the energetic ordering of orbitals in multi-electron atoms

A wave-function can have positive and negative values

"Radial nodes" can appear in radial probability distribution functions

The shape of an orbital is given by the principal quantum number

Splitting of spectral lines under the influence of electric field is known as;

Zeeman effect

Stark effect

Photoelectric effect

Screening effect

The energies E1 and E2 of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths i.e., λ1 and λ2 will be:

λ1 = λ2

λ1 = 2λ2

λ1 = 4λ2

λ1 = (1/2)λ2

If the electron in a hydrogen atom drops from the n = 6 to the n = 4 level, the radiation emitted is in which series of lines in the spectrum of atomic hydrogen?

Lyman

Balmer

Paschen

Brackett

In order to increase the kinetic energy of ejected photoelectrons, there should be an increase in;

intensity of radiation.

wavelength of radiation.

frequency of radiation.

both wavelength and intensity of radiation.

In which of the following case would the probability of finding an electron residing in a dxy orbital be zero?

XY and YZ plane

XY and XZ plane

XZ and YZ plane

All of these

The maximum number of 4d electrons having spin quantum number +1/2 are

The basis of three unpaired electrons present in the configuration of nitrogen is

Aufbau principle

Pauli's principle

Hund's rule of maximum multiplicity

Uncertainty principle

Given below are two statements: Statement I: Bohr’s theory accounts for the stability and line spectrum of Li⁺ ion. Statement II: Bohr’s theory was unable to explain the splitting of spectral lines in the presence of a magnetic field. In the light of the above statements, choose the most appropriate answer from the options given below.

Statement I is correct, but Statement II is incorrect.

Statement I is incorrect, but Statement II is correct.

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect.

Which of the following sets of quantum number is incorrect? I. n = 5, l = 4, m = 0, s = +1/2 II. n = 3, l = 3, m = +3, s = +1/2 III. n = 6, l = 0, m = +1, s = –1/2 IV. n = 4, l = 2, m = +2, s = 0

II and IV only

I, II and III only

II, III and IV only

I and III only

If the uncertainty in velocity and position are same, then the uncertainty in momentum would be:

hm/4π

h/m4π

h/4mπ

h/4πm

The total number of subshells in the nth energy level is;

n²

2n²

n–1

Which of the following subshell can accommodate as many as 10 electrons?

3dxy

3dz²

Select the incorrect statement(s):

An electron near the nucleus is attracted by the nucleus and has a low potential energy

According to Bohr's theory, an electron continuously radiate energy if it stays in one orbit.

Bohr's model could not explain the spectra of multielectron atoms.

Bohr's model was the first atomic model based on quantisation of energy

If the radius of the 3rd orbit of Li2+ ion is x, then find the radius of the 1st orbit of He+ ion in terms of x;

x/8

x/6

5x/8

7x/8

The quantum number which decides the orientation of an orbital in space is:

Principal quantum number

Azimuthal quantum number

Magnetic quantum number

Spin quantum number

The increasing order of filling of electrons in the orbitals of an atom will be;

3d, 4s, 4p, 4d, 5s

4s, 3d, 4p, 5s, 4d

4s, 4p, 3d, 4d, 5s

3d, 4p, 4s, 4d, 5s

If the value of (n + l) is more than 3 and less than 6, then what will be the possible number of orbitals?

The ratio of minimum to maximum wavelengths in Balmer series of H-atom is;

5 : 9

5 : 36

1 : 4

3 : 4

If the radius of the first Bohr orbit of the H atom is ‘x Å’, then the radius (in Å) of the first orbit of He⁺ ion will be:

x/2

x/3

Given below are two statements: Statement I: Positive ions are formed from their neutral parent atom by the loss of electrons. Statement II: Cathode rays move from positive electrode to negative electrode. In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I is correct but Statement II is incorrect.

Statement I is incorrect but Statement II is correct.

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect.

The frequency of radiation emitted when the electron falls from n = 4 to n = 1 in a hydrogen atom will be;

2 × 10¹⁵ s⁻¹

1.54 × 10¹⁵ s⁻¹

1.03 × 10¹⁵ s⁻¹

3.08 × 10¹⁵ s⁻¹

The ionization energy of H atom is 13.6 eV. The ionization energy of Li2+ ion will be;

54.4 eV

40.8 eV

27.2 eV

122.4 eV

The number of orbitals in a subshell having azimuthal quantum number l = 3 is:

In the ground state, an element has 13 electrons in its M shell. The element is

cobalt

chromium

nickel

iron

Which of the following sets of quantum number is(are) incorrect?

n = 5, l = 4, m = 0, s = +1/2

n = 3, l = 3, m = +3, s = +1/2

n = 6, l = 0, m = +1, s = –1/2

n = 4, l = 2, m = +2, s = 0

The number of radial nodes of 3s, 3p and 3d orbitals are, respectively:

0, 1, 2

2, 1, 0

2, 2, 2

1, 3, 5

Given below are two statements: Statement I: For a particular shell, maximum number of orbital is n² Statement II: For d-subshell, number of orientation lies between –l to +l including zero. In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I is correct but Statement II is incorrect.

Statement I is incorrect but Statement II is correct.

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect.

The energy of a photon is directly proportional to: I. wave number II. frequency III. wavelength Select the correct option.

Both I and II

Both I and III

Both II and III

II only

The number of orbitals associated with quantum number n = 5, ms = 1/2 is;

From the α-particle scattering experiment, Rutherford concluded that:

The radius of the atom is about 10⁻¹⁰ m

The radius of the nucleus is less than 10⁻¹⁴ m

Most of the space in atom is empty.

All of these

Which of the following statement is correct regarding Heisenberg’s uncertainty principle?

It is possible to determine simultaneously the exact position and exact momentum of an electron.

It is not possible to determine simultaneously the exact position and exact momentum of an electron.

It is possible to determine exact position but not momentum.

It is possible to determine exact momentum but not position.

(A) and (C) only

(A) and (B) only

(B) and (D) only

The orbital with maximum energy is;

Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Threshold frequency is the maximum frequency required for the ejection of electron from the metal surface. Reason (R): Threshold frequency is the characteristic of a metal. In the light of the above statements, choose the correct answer from the options given below:

A is true but R is false.

A is false but R is true.

Both A and R are true and R is the correct explanation of A.

Both A and R are true but R is NOT the correct explanation of A.

Which of the following statements is incorrect for anode rays?

They are deflected by electric and magnetic fields.

Their e/m ratio depends on the gas in the discharge tube used to produce the anode rays.

The e/m ratio of anode rays is constant.

They are produced by the ionization of the gas in the discharge tube.

A hydrogen-like ion produces a spectral line with one-fourth the wavelength of a corresponding line in hydrogen for the same electronic transition. Identify the species.

He⁺

Be³⁺

Li²⁺

B⁴⁺

Total number of electrons present in 24Cr and 29Cu having quantum number l = 2 and m = 0

Which of the following quantum numbers is not possible?

n = 3, l = 2, m = –2

n = 4, l = 3, m = 0

n = 2, l = 2, m = 1

n = 3, l = 1, m = 0

Read the following statements and choose the correct option: (I) If the radius of the first Bohr orbit of hydrogen atom is r, then radius of 2nd orbit of Li2+ would be 4r. (II) For s-orbital, the orbital angular momentum is zero.

only I is correct

only II is correct

both are correct

both are incorrect

Given below are two statements: Statement I: In fourth energy level there is no f subshell. Statement II: For n = 3, the possible value of l are 0,1 and 2. In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I is correct but Statement II is incorrect.

Statement I is incorrect but Statement II is correct.

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect.

The kinetic and potential energy (in eV) of electron present in third Bohr’s orbit of hydrogen atom are respectively;

–1.51, –3.02

1.51, –3.02

–3.02, 1.51

1.51, –1.51

Which of the following statements is correct?

Probability of finding an electron at the nucleus is zero for all orbitals.

Probability of finding an electron at the nucleus is maximum for p-orbitals.

Probability of finding an electron at the nucleus is non-zero for s-orbitals.

Probability of finding an electron at the nucleus is same for all orbitals.

Match List I with List II List-I (Atomic models) A. Thomson Model B. Rutherford Model C. Bohr Model D. Quantum Mechanical Model List-II (Key features) I. Electrons embedded in a positive sphere II. Planetary model with a central dense nucleus III. Quantized energy levels for electrons IV. Orbitals and probability distributions Choose the correct answer from the options given below:

A-I, B-II, C-III, D-IV

A-IV, B-III, C-I, D-II

A-III, B-IV, C-II, D-I

A-II, B-I, C-IV, D-III

Consider the ground state of Cr atom (Z = 24). The numbers of electrons with the azimuthal quantum numbers, l = 1 and 2 are, respectively

16 and 5

12 and 5

16 and 4

12 and 4

Maximum number of electrons in a subshell with l = 3 and n = 4 is:

Which one is the wrong statement?

The energy of 2s orbital is less than the energy of 2p orbital in case of hydrogen like atoms

s-orbital is spherical.

The uncertainty principle is Δx Δp ≥ h/4π

Half-filled and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement

Which of the following properties of atom could be explained correctly by Thomson model of atom?

Overall neutrality of atom

Spectra of hydrogen atom

Position of electrons, protons and neutrons in atom

Stability of atom

Which of the following statements does not form part of Bohr's model of the hydrogen atom

The angular momentum of an electrons is quantized

The radii for stationary state for H-atom is r = n²a₀

Electrons revolve in different orbits around the nucleus

The position and velocity of the electrons in the orbit cannot be determined simultaneously

The number of protons, neutrons and electrons in 71Lu175 respectively, are;

104, 71 and 71

71, 71 and 104

175, 104 and 71

71, 104 and 71

Given below are two statements: Statement I: Orbital having xz plane as node may be 3dxy. Statement II: 3dxy has zero radial node. In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I is correct but Statement II is incorrect.

Statement I is incorrect but Statement II is correct.

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect.

Which of the following groupings represent a collection of isoelectronic species ?

N³⁻ , F⁻ , Na⁺

Be , Al³⁺ , Cl⁻

Ca²⁺ , Cs⁺ , Br⁻

Na⁺ , Ca²⁺ , Mg²⁺

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: Emitted radiations will fall in visible range when an electron jumps from higher energy level to n = 2 energy level in H-atom. Reason R: Balmer series radiations belong to visible range incase of H-like species. In the light of the above statements, choose the correct answer from the options given below:

A is true but R is false.

A is false but R is true.

Both A and R are true and R is the correct explanation of A.

Both A and R are true but R is NOT the correct explanation of A.

Uncertainty in position of a particle of 25 gram in space is 10–5 m. Hence uncertainty in velocity (m/sec) is (h = 6.6 × 10–34 J sec)

2.1 × 10–28

2.1 × 10–34

0.5 × 10–34

5 × 10–24

(A), (B), (C) and (E) only

(A), (D) and (E) only

(B) and (E) only

(B), (C) and (E) only

The principle, which gives a way to fill the electrons in the available energy level is;

Hunds rule

Paulis exclusion principle

Aufbau principle

None of these

Number of radial/spherical nodes present in 5f orbital is:

A ball of mass 200 g is moving with a velocity of 10 m s⁻¹. If the error in measurement of velocity is 0.1%, the minimum uncertainty in its position is:

3.3 × 10⁻³¹ m

3.3 × 10⁻²⁷ m

5.3 × 10⁻²⁵ m

2.64 × 10⁻³² m

The orientation of an atomic orbital is governed by;

magnetic quantum number.

principal quantum number.

azimuthal quantum number.

spin quantum number.

The velocity of particle A is 0.1 m/sec and that of particle B is 0.05 m/sec. If the mass of particle B is 5 times that of particle A, then the ratio of de-Broglie wavelength associated with particle A and B;

2:5

3:4

6:4

5:2

Given below are two statements: Statement I: The de Broglie equation suggests that an electron has particle-wave duality. Statement II: If the uncertainty in position of a moving particle is 0, then Δp = Infinite. In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I is correct but Statement II is incorrect.

Statement I is incorrect but Statement II is correct.

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect.

Match List-I with List-II: List-I List-II (A) Number of electrons in an orbit (I) 0.529 × n²/Z Å (B) Bohr’s radius of an orbit (II) 2n² (C) Angular momentum of an electron (III) h/mv (D) de Broglie wavelength (IV) nh/2π Choose the correct answer from the options given below:

A-III, B-IV, C-I, D-II

A-II, B-I, C-IV, D-III

A-IV, B-III, C-I, D-II

A-I, B-II, C-IV, D-III

Which of the following is the correct order of energy of orbitals?

What is maximum number of electrons accommodated in a subshell having azimuthal quantum number, l = 2?

The ratio of spacing between the third and fourth orbit to the spacing between sixth and seventh orbit of H-atom is

7 : 13

13 : 7

16 : 49

1 : 1

Arrange the following orbitals of H-atom in the increasing order of their energy; 3px, 2s, 4dxy, 3s, 4pz, 3py, 4s

Number of possible spectral lines in the brackett series in hydrogen spectrum, when electrons present in the ninth excited state return to the ground state, is

Which of the following statements correctly describes the Bohr model of the atom?

Electrons orbit the nucleus in fixed circular paths with increasing energy levels further from the nucleus.

Electrons are found in probabilistic clouds around the nucleus.

Electrons have a definite position and momentum at any given time.

Electrons move in elliptical orbits around the nucleus.

The threshold frequency for a metal is 7.0 × 10¹⁴ s⁻¹. Calculate the kinetic energy of an electron emitted when radiation of frequency 1.0 × 10¹⁵ s⁻¹ hits the metal.

1.98 × 10⁻¹⁸ J

1.98 × 10⁻¹⁹ J

2 × 10⁻¹⁶ J

2 × 10⁻¹⁹ J

Given below are two statements: Statement I: A spectral line will be observed for a 2px → 2py transition. Statement II: 2px and 2py are degenerate orbitals. In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I is correct but Statement II is incorrect.

Statement I is incorrect but Statement II is correct.

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect.

The radius of the second orbit of H-atom is equal to the radius of;

second orbit of He+ ion.

third orbit of Li2+ ion.

fourth orbit of He+ ion.

fourth orbit of Be3+ ion.

Which of the following configuration is violating Pauli’s exclusion principle?

(1)

(2)

(3)

(2) and (3)

Statement I is incorrect but statement II is correct.

Statement I is correct but statement II is incorrect.

Both statement I and statement II are incorrect.

Both statements I and statement II are correct.

Select the correct statement(s); A. Heisenberg’s principle is applicable to stationary electron B. Paulis exclusion principle is not applicable to photons C. For an electron the product of velocity and principal quantum number will be independent to principal quantum number D. Quantum numbers l and m determine the value of angular wave function

A only

A, B only

D only

B, C, D only

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R: Assertion A: The characteristics of cathode rays do not depend upon the nature of material of electrodes. Reason R: Cathode rays consist of positively charged particles, called protons. In the light of the above statements, choose the correct answer from the options given below:

A is true but R is false.

A is false but R is true.

Both A and R are true and R is the correct explanation of A.

Both A and R are true but R is NOT the correct explanation of A.

Which orbital is non-directional?

All of these

The magnetic quantum number for the last electron in sodium is;

Zero

Which of the following properties of atom could be explained correctly by Thomson model of atom?

Overall neutrality of atom.

Spectra of hydrogen atom.

Position of electrons, protons and neutrons in atom.

Stability of atom.

100

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: According to de-Broglie, the wavelengths associated with electrons and other subatomic particles can be detected experimentally. Reason R: The wavelength associated with any material particle is directly proportional to its mass. In the light of the above statements, choose the correct answer from the options given below:

A is true but R is false.

A is false but R is true.

Both A and R are true and R is the correct explanation of A.

Both A and R are true but R is NOT the correct explanation of A.

101

−3.4 eV

−6.8 eV

−13.6 eV

−27.2 eV

102

The wavelength of light associated with a photon of energy 3.3 × 10⁻¹⁹ J is:

6.0 × 10⁻⁷ m

5.0 × 10⁻⁷ m

4.0 × 10⁻⁷ m

3.0 × 10⁻⁷ m

103

A-III, B-II, C-I, D-IV

A-II, B-IV, C-I, D-III

A-I, B-III, C-IV, D-II

A-IV, B-I, C-II, D-III