15
MCQ (Single Correct Answer)
For the electrons of oxygen atom, which of the following statements is correct?
A
$Z_{\text {eff }}$ for an electron in a $2 s$ orbital is the same as $Z_{\text {eff }}$ for an electron in a $2 p$ orbital
B
An electron in the $2 s$ orbital has the same energy as an electron in the $2 p$ orbital
C
$Z_{\text {eff }}$ for an electron in $1 s$ orbital is the same as $Z_{\text {eff }}$ for an electron in a $2 s$ orbital
D
The two electrons present in the $2 s$ orbital have spin quantum numbers $m_s$ but of opposite sign
16
MCQ (Single Correct Answer)
If travelling at same speeds, which of the following matter waves have the shortest wavelength?
A
Electron
B
Alpha particle $\left(\mathrm{He}^{2+}\right)$
C
Neutron
D
Proton
17
MCQ (Multiple Correct Answer)
Identify the pairs which are not of isotopes?
A
${ }_6^{12} X,{ }_6^{13} Y$
B
${ }_{17}^{35} X,{ }_{17}^{37} Y$
C
${ }_6^{14} X,{ }_7^{14} Y$
D
${ }_4^8 X,{ }_5^8 Y$
18
MCQ (Multiple Correct Answer)
Out of the following pairs of electrons, identify the pairs of electrons present in degenerate orbitals.
A
(i) $n=3, l=2, m_l=-2, m_s=-\frac{1}{2}$
(ii) $n=3, l=2, m_l=-1, m_s=-\frac{1}{2}$
B
(i) $n=3, l=1, m_l=1, m_s=+\frac{1}{2}$
(ii) $n=3, l=2, m_l=1, m_s=+\frac{1}{2}$
C
(i) $n=4, l=1, m_l=1, m_s=+\frac{1}{2}$
(ii) $n=3, l=2, m_l=1, m_s=+\frac{1}{2}$
D
(i) $n=3, l=2, m_l=+2, m_s=-\frac{1}{2}$
(ii) $n=3, l=2, m_l=+2, m_s=+\frac{1}{2}$
19
MCQ (Multiple Correct Answer)
Which of the following sets of quantum numbers are correct?
A
| $n$ | $l$ | $m$ |
|---|---|---|
| 1 | 1 | +2 |
B
| $n$ | $l$ | $m$ |
|---|---|---|
| 2 | 1 | +1 |
C
| $n$ | $l$ | $m$ |
|---|---|---|
| 3 | 2 | $-$2 |
D
| $n$ | $l$ | $m$ |
|---|---|---|
| 3 | 4 | $-$2 |