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43
Subjective

Match the quantum numbers with the information provided by these.

Quantum number Information provided
A. Principal quantum number 1. Orientation of the orbital
B. Azimuthal quantum number 2. Energy and size of orbital
C. Magnetic quantum number 3. Spin of electron
D. Spin quantum number 4. Shape of the orbital

Explanation

A. $\rightarrow$ (2)

B. $\rightarrow(4)$

C. $\rightarrow(1)$

D. $\rightarrow$ (3)

A. Principal quantum number is the most important quantum number as it determines the size and to large extent the energy of the orbital.

B. Azimuthal quantum number determines the angular momentum of the electron and defines the three-dimensional shape of the orbital.

C. Magnetic quantum number gives information about the spatial orientation of orbitals with respect to a standard set of coordinate axes.

D. Spin quantum number arises from the spectral evidence that an electron in its motion around the nucleus in an orbit also rotates or spin about its own axis.

44
Subjective

Match the following rules with their statements.

Rules Statements
A. Hund's Rule 1. No two electrons in an atom can have the same set of four quantum numbers.
B. Aufbau Principle 2. Half-filled and completely filled orbitals have extra stabilty.
C. Pauli Exclusion Principle 3. Pairing of electrons in the orbitals belonging to the same subshell does not take place until each orbital is singly occupied.
D. Heisenberg's Uncertainty Principle 4. It is impossible to determine the exact position and exact momentum of a subatomic particle simultaneously.
5. In the ground state of atoms, orbitals are filled in the order of their increasing energies.

Explanation

A. $\rightarrow$ (3)

B. $\rightarrow$ (5)

C. $\rightarrow$ (1)

D. $\rightarrow$ (4)

A. Hund's rule states that pairing of electrons in the orbitals belonging to the same subshell ( $p, d$ or $f$ ) does not take place until each orbital belonging to that subshell has got one electron each i.e., it is singly occupied.

B. Aufbau principle states that in the ground state of the atoms, the orbitals are filled in order of their increasing energies.

C. According to Pauli exclusion principle, no two electrons in an atom can have the same set of four quantum numbers.

D. Heisenberg's uncertainty principle states that it is impossible to determine the exact position and exact momentum of a subatomic particle simultaneously.

45
Subjective

Match the following.

Column I Column II
A. X-rays 1. $$v=10^0-10^4$$ Hz
B. Ultraviolet wave (UV) 2. $$v=10^{10}$$ Hz
C. Long radio waves 3. $$v=10^{16}$$ Hz
D. Microwave 4. $$v=10^{18}$$ Hz

Explanation

A. $\rightarrow(4)$

B. $\rightarrow(3)$

C. $\rightarrow$ (1)

D. $\rightarrow(2)$

Name Frequency Uses
A. X-rays $$
2 \times 10^{16}-3 \times 10^{19} \mathrm{~Hz}
$$
Medical pictures, material testing
B. Ultraviolet wave (UV) $$
7.9 \times 10^{14}-2 \times 10^{16} \mathrm{~Hz}
$$
Germisidal lamp
C. Long radio waves $$
10^0-10^4 \mathrm{~Hz}
$$
Signal transmission
D. Microwave $$
1 \times 10^9-5 \times 10^{11} \mathrm{~Hz}
$$
Cooking radar

46
Subjective

Match the following.

Column I Column II
A. Photon 1. Value is 4 for N-shell
B. Electron 2. Probability density
C. $${\psi ^2}$$ 3. Always positive value
D. Principle quantum number n 4. Exhibits both momentum and wavelength

Explanation

A. $\rightarrow(4)$

B. $\rightarrow$ (4)

C. $\rightarrow(2,3)$

D. $\rightarrow(1,3)$

A. Photon has particle nature as well as wave nature. It exhibits both momentum and wavelength.

B. Electron also has particle nature as well as wave nature. Thus, it also exhibits both momentum and wavelength.

C. $\psi^2$ represents probability density of electron and always has positive values.

D. Principal quantum number $n=4$ for $N$-shell.

$$\begin{array}{rrrr} & \mathrm{K} &\mathrm{L} & \mathrm{M} & \mathrm{N} \\ & n=\quad 1 & 2 & 3 & 4 \end{array}$$

It always has positive values.

47
Subjective

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

Column Column II
A. Cr 1. $$
[\operatorname{Ar}] 3 d^8 4 s^0
$$
B. Fe$$^{2+}$$ 2. $$
[\operatorname{Ar}] 3 d^{10} 4 s^1
$$
C. Ni$$^{2+}$$ 3. $$
[\operatorname{Ar}] 3 d^6 4 s^0
$$
D. Cu 4. $$
[\operatorname{Ar}] 3 d^5 4 s^1
$$
5. $$
[\operatorname{Ar}] 3 d^6 4 s^2
$$

Explanation

A. $\rightarrow(4)$

B. $\rightarrow$ (3)

C. $\rightarrow(1)$

D. $\rightarrow(2)$

A. $\operatorname{Cr}(Z=24)=1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^5 4 s^1=[\operatorname{Ar}] 3 d^5 4 s^1$

B. $\mathrm{Fe}^{2+}(Z=26)=1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^6 4 s^0=[\operatorname{Ar}] 3 d^6 4 s^0$

C. $\mathrm{Ni}^{2+}(Z=28)=1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^8 4 s^0=[\mathrm{Ar}] 3 d^8 4 s^0$

D. $\mathrm{Cu}(Z=29)=1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^{10} 4 s^1=[\mathrm{Ar}] 3 d^{10} 4 s^1$