Chapter 2: Structure of Atom

Q42Written answer

Match the following species with their corresponding ground state electronic configuration. Atom / Ion Electronic configuration

(i) Cu (a)1s2 2s2 2p6 3s2 3p6 3d10

(ii) Cu2+ (b) 1s2 2s2 2p6 3s2 3p6 3d10 4s2

(iii) Zn2+ (c) 1s2 2s2 2p6 3s2 3p6 3d10 4s1

(iv) Cr3+ (d) 1s2 2s2 2p6 3s2 3p6 3d9

(e) 1s2 2s2 2p6 3s2 3p6 3d3

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(i) Cu	(c) 1s2 2s2 2p6 3s2 3p6 3d10 4s1
(ii) Cu2+	(d) 1s2 2s2 2p6 3s2 3p6 3d9
(iii) Zn2+	(a)1s2 2s2 2p6 3s2 3p6 3d10
(iv) Cr3+	(e) 1s2 2s2 2p6 3s2 3p6 3d3

Q43Written answer

Match the quantum numbers with the information provided by these. Quantum number Information provided

(i) Principal quantum number (a) orientation of the orbital

(ii) Azimuthal quantum number (b) energy and size of orbital

(iii) Magnetic quantum number (c) spin of electron

(iv) Spin quantum number (d) shape of the orbital

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(i) Principal quantum number	(b) energy and size of orbital
(ii) Azimuthal quantum number	(d) shape of the orbital
(iii) Magnetic quantum number	(a) orientation of the orbital
(iv) Spin quantum number	(c) spin of electron

Q44Written answer

Match the following rules with their statements :

Rules	Statements
(i) Hund’s Rule	(a) No two electrons in an atom can have the same set of four quantum numbers.
(ii) Aufbau Principle	(b) Half-filled and completely filled orbitals have extra stability.
(iii) Pauli Exclusion Principle	(c) Pairing of electrons in the orbitals belonging to the same subshell does not take place until each orbital is singly occupied.
(iv) Heisenberg’s Uncertainty Principle	(d) It is impossible to determine the exact position and exact momentum of a subatomic particle simultaneously
	(e) In the ground state of atoms, orbitals are filled in the order of their increasing energies.

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(i) Hund’s Rule	(c) Pairing of electrons in the orbitals belonging to the same subshell does not take place until each orbital is singly occupied.
(ii) Aufbau Principle	(e) In the ground state of atoms, orbitals are filled in the order of their increasing energies.
(iii) Pauli Exclusion Principle	(a) No two electrons in an atom can have the same set of four quantum numbers.
(iv) Heisenberg’s Uncertainty Principle	(d) It is impossible to determine the exact position and exact momentum of a subatomic particle simultaneously

Q45Written answer

Match the following

i) X-rays	(a) ν = 100-104 Hz
ii) UV	(b) ν = 1010 Hz
iii) Long radio waves	(c) ν = 1016Hz
iv) Microwave	(d) ν = 1018Hz

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i) X-rays	(d) ν = 1018Hz
ii) UV	(c) ν = 1016Hz
iii) Long radio waves	(a) ν = 100-104 Hz
iv) Microwave	(b) ν = 1010 Hz

Q46Written answer

Match the following

(i) Photon	(a) Value is 4 for N shell
(ii) Electron	(b) Probability density
(iii) ψ 2	(c) Always positive value
(iv) Principal quantum number n	(d) Exhibits both momentum and wavelength

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(i) Photon	(d) Exhibits both momentum and wavelength
(ii) Electron	(d) Exhibits both momentum and wavelength
(iii) ψ 2	(b) Probability density (c) Always positive value
(iv) Principal quantum number n	(a) Value is 4 for N shell (c) Always positive value

Q47Written answer

Match species given in Column I with the electronic configuration given in Column II

Column I	Column II
(i) Cr	(a) [Ar]3d84s0
(ii)Fe2+	(b) [Ar]3d104s1
(iii)Ni2+	(c) [Ar]3d64s0
(iv)Cu	(d) [Ar] 3d54s1
	(e) [Ar]3d64s2

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(i) Cr	(d) [Ar] 3d54s1
(ii)Fe2+	(c) [Ar]3d64s0
(iii)Ni2+	(a) [Ar]3d84s0
(iv)Cu	(b) [Ar]3d104s1

Assertion and Reason Type

Q48Written answer

Assertion (A) : All isotopes of a given element show the same type of chemical behaviour.

Reason (R) : The chemical properties of an atom are controlled by the number of electrons in the atom.

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

(ii) Both A and R are true but R is not the correct explanation of A.

(iii) A is true but R is false.

(iv) Both A and R are false.

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Ans: (i)

As the chemical properties depend upon the number of electrons present in the atom thus the isotopes resemble the same chemical properties as they have the same number of electrons i.e. atomic number.

Q49Written answer

Assertion (A) : Black body is an ideal body that emits and absorbs radiations of all frequencies.

Reason (R) : The frequency of radiation emitted by a body goes from a lower frequency to higher frequency with an increase in temperature.

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

(ii) Both A and R are true but R is not the explanation of A.

(iii) A is true and R is false.

(iv) Both A and R are false.

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Ans: (ii)

The black body is the ideal body that absorbs and emits radiation of all frequencies. The radiation that it emits is said to be black body radiation.

With an increase of temperature the frequency of the black body radiation increases.

Q50Written answer

Assertion (A) : It is impossible to determine the exact position and exact momentum of an electron simultaneously.

Reason (R) : The path of an electron in an atom is clearly defined.

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

(ii) Both A and R are true and R is not the correct explanation of A.

(iii) A is true and R is false.

(iv) Both A and R are false.

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Ans: (iii)

According to Heisenberg's uncertainty principle it is impossible to determine simultaneously the exact position and exact momentum (or velocity) of an electron. Thus it implies that determining the trajectory of an electron is impossible as it requires exact position and velocity which is not possible as per the uncertainty principle.

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