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

(i) The rule states that for a given electron configuration, the lowest energy term is the one with the greatest value of spin multiplicity. This implies that if two or more orbitals of equal energy are available, electrons will occupy them singly before filling them in pairs. (ii) The Aufbau principle states that electrons fill lower-energy atomic orbitals before filling higher-energy ones. By following this rule, we can predict the electron configurations for atoms or ions. (iii) Pauli's Exclusion Principle states that no two electrons in the same atom can have identical values for all four of their quantum numbers. (iv) The Heisenberg Uncertainty Principle states that it is impossible to determine simultaneously, the exact position and exact momentum (or velocity) of an electron. Rules Statements (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.

Match the following: (i) X-rays (a) v = 10 0 - 10 4 Hz (ii) UV (b) v = 10 10 Hz (iii) Long radio waves (c) v = 10 16 Hz (iv) Microwave (d) v = 10 18 Hz

(i) X-rays region around 10 18 Hz . The most familiar use of X-rays is checking for fractures (broken bones), but X-rays are also used in other ways. For example, chest X-rays can spot pneumonia. Mammograms use X-rays to look for breast cancer. (ii) Ultraviolet region around 10 16 Hz , a component of sun’s radiation. UV radiation is present in sunlight, and constitutes about 10 % of the total electromagnetic radiation output from the Sun. (iii) Long radio waves frequency region around 10 0 - 10 4 Hz , used in standard broadcast radio and television, shortwave radio, navigation and air-traffic control, cellular telephony, and even remote-controlled toys. (iv) Microwave region around 10 10 Hz , used for radar. Microwaves have short wavelength hence low energy dispersion during long distance communication. Thus they are used in radar system. (i) X-rays (d) ν = 10 18 Hz (ii) UV (c) ν = 10 16 Hz (iii) Long radio waves (a) ν = 10 0 – 10 4 Hz (iv) Microwave (b) ν = 10 10 Hz

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

According to the de-Broglie wavelength of a particle or a photon, λ = h mv , molecules with a very small mass, exhibit both wave and particle nature, hence electron which has very less mass exhibits both momentum and wavelength. ψ 2 is the probability of finding an electron in a particular location in an atom, and always has a positive value. The probability density is a measure of the likelihood that a particle will be found at a particular location in space. In this case, where you would likely find an electron in the electron cloud. Principal quantum number ' n ' denotes the energy level (or) shell number, if n = 4 , the electron belongs to N shell. The value of ' n ' is always positive. (i) Photon (d) Exhibits both momentum and wavelength (ii) Electron (d) Exhibits both momentum and wavelength (iii) ψ 2 (b) (c) Probability density Always positive value (iv) Principal quantum number n (a) (c) Value is 4 for N shell Always positive value

Match species given in Column I with the electronic configuration given in Column II. Column I Column II (i) Cr (a) [ Ar ] 3 d 8 4 s 0 (ii) Fe 2 + (b) [ Ar ] 3 d 10 4 s 1 (iii) Ni 2 + (c) [ Ar ] 3 d 6 4 s 0 (iv) Cu (d) [ Ar ] 3 d 5 4 s 1 (e) [ Ar ] 3 d 6 4 s 2

(i) Cr has atomic number 24 , therefore its electronic configuration is Ar 3 d 5 4 s 1 . Atom/Ion Electronic configuration (i) Cr (d) Ar 3 d 5 4 s 1 (ii) Fe + 2 has two electrons less than the ground state Iron atom, therefore its electronic configuration is Ar 3 d 6 4 s 0 Atom/Ion Electronic configuration (ii) Fe + 2 (c) Ar 3 d 6 4 s 0 (iii) Ni + 2 has two electrons less than the ground state Nickel ( 28 ) atom; therefore its electronic configurations is Ar 3 d 8 4 s 0 . Atom/Ion Electronic configuration (iii) Ni + 2 (a) Ar 3 d 8 4 s 0 (iv) Cu ( 29 ) atom; therefore, its electronic configuration is Ar 3 d 10 4 s 1 Atom/Ion Electronic configuration (iv) Cu (b) Ar 3 d 10 4 s 1 Column I Column II (i) Cr (d) [ Ar ] 3 d 5 4 s 1 (ii) Fe 2 + (c) [ Ar ] 3 d 6 4 s 0 (iii) Ni 2 + (a) [ Ar ] 3 d 8 4 s 0 (iv) Cu (b) [ Ar ] 3 d 10 4 s 1

EASY

11th CBSE

IMPORTANT

Earn 100

Match the quantum numbers with the information provided by these.

Quantum Number Information Provided

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

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

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

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

Important Questions on Structure of Atom

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 2 - Structure of Atom>Matching Type>Q 44

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

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 2 - Structure of Atom>Matching Type>Q 45

Match the following:

(i)	X-rays	(a)	$v = 10^{0} - 10^{4} Hz$
(ii)	UV	(b)	$v = 10^{10} Hz$
(iii)	Long radio waves	(c)	$v = 10^{16} Hz$
(iv)	Microwave	(d)	$v = 10^{18} Hz$

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 2 - Structure of Atom>Matching Type>Q 46

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

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 2 - Structure of Atom>Matching Type>Q 47

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

Column I		Column II
(i)	$Cr$	(a)	$[Ar] 3 d^{8} 4 s^{0}$
(ii)	${Fe}^{2 +}$	(b)	$[Ar] 3 d^{10} 4 s^{1}$
(iii)	${Ni}^{2 +}$	(c)	$[Ar] 3 d^{6} 4 s^{0}$
(iv)	$Cu$	(d)	$[Ar] 3 d^{5} 4 s^{1}$
		(e)	$[Ar] 3 d^{6} 4 s^{2}$

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 2 - Structure of Atom>Long Answer Type>Q 51

What is photoelectric effect? State the result of photoelectric effect experiment that could not be explained on the basis of laws of classical physics. Explain this effect on the basis of quantum theory of electromagnetic radiations.

HARD

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 2 - Structure of Atom>Long Answer Type>Q 52

Threshold frequency,

ν_{0}

is the minimum frequency which a photon must possess to eject an electron from a metal. It is different for different metals. When a photon of frequency

1.0 \times 10^{15} s^{- 1}

was allowed to hit a metal surface, an electron having

1.988 \times 10^{- 19} J

of kinetic energy was emitted. Calculate the threshold frequency of this metal. Show that an electron will not be emitted if a photon with a wavelength equal to

600 nm

hits the metal surface.

HARD

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 2 - Structure of Atom>Long Answer Type>Q 53

When an electric discharge is passed through hydrogen gas, the hydrogen molecules dissociate to produce excited hydrogen atoms. These excited atoms emit electromagnetic radiation of discrete frequencies which can be given by the general formula.

$\bar{ν} = 109677 (\frac{1}{n_{i}^{2}} - \frac{1}{n_{f}^{2}})$

What points of Bohr’s model of an atom can be used to arrive at this formula? Based on these points derive the above formula giving description of each step and each term.

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 2 - Structure of Atom>Long Answer Type>Q 54

Calculate the energy and frequency of the radiation emitted when an electron jumps from

n = 3

n = 2

in a hydrogen atom.

Quantum Number		Information Provided
(a)	Principal quantum number	(p)	orientation of the orbital
(b)	Azimuthal quantum number	(q)	energy and size of orbital
(c)	Magnetic quantum number	(r)	spin of electron
(d)	Spin quantum number	(s)	shape of the orbital

Important Questions on Structure of Atom

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