MCQ

MCQ 11 Mark

What does magnetic quantum number describe ?

A
Shape of an orbital
B
Size of an orbital
C
Spin of an electron
✓
Orientation of an orbital in the given subshell

Answer

Correct option: D.

Orientation of an orbital in the given subshell

View full question & answer→

MCQ 21 Mark

Which of the following is not hydrogen like species?

A
$\mathrm{He}^{+}$
B
$\mathrm{Be}^{3+}$
C
$\mathrm{Li}^{2+}$
✓
$\mathrm{He}$

Answer

Correct option: D.

$\mathrm{He}$

View full question & answer→

MCQ 31 Mark

Calculate the radius of first orbit of $\mathrm{Be}^{3+}$

✓
$13.23 \mathrm{pm}$
B
$52.9 \mathrm{pm}$
C
$17.63 \mathrm{pm}$
D
$26.45 \mathrm{pm}$

Answer

Correct option: A.

$13.23 \mathrm{pm}$

View full question & answer→

MCQ 41 Mark

What is the number of nucleons present in an atom having 29 electrons and 34 neutrons in it?

A
34
B
5
✓
63
D
29

Answer

Correct option: C.

View full question & answer→

MCQ 51 Mark

A
(a)-(i),(b)-(ii),(c)-(iv),(d)-(iii)
B
(a)-(ii),(b)-(iii),(c)-(i),(d)-(iv)
✓
(a)-(iii),(b)-(iv),(c)-(ii),(d) - (i)
D
(a)-(iv),(b)-(i),(c)-(iii),(d) - (ii)

Answer

Correct option: C.

(a)-(iii),(b)-(iv),(c)-(ii),(d) - (i)

View full question & answer→

MCQ 61 Mark

What is the energy associated with first orbit of $Li ^{2+}\left( R _{ H }=2.18 \times 10^{-18}\right) ?$

✓
$-19.62 \times 10^{-18} \mathrm{~J}$
B
$-34.88 \times 10^{-18} \mathrm{~J} $
C
$-2.18 \times 10^{-18} \mathrm{~J}$
D
$-8.72 \times 10^{-18} \mathrm{~J}$

Answer

Correct option: A.

$-19.62 \times 10^{-18} \mathrm{~J}$

View full question & answer→

MCQ 71 Mark

Which among the following statements is TRUE about isotones?

A
These have same chemical properties.
B
These occupy same positions in the modern periodic table.
✓
These are nuclides having the same number of neutrons but different number of protons and hence different mass numbers.
D
These have different number of neutrons and same number of protons.

Answer

Correct option: C.

These are nuclides having the same number of neutrons but different number of protons and hence different mass numbers.

View full question & answer→

MCQ 81 Mark

Principal Quantum number describes

A
shape of orbital
✓
size of the orbital
C
spin of electron
D
orientation of in the orbital electron cloud

Answer

Correct option: B.

size of the orbital

View full question & answer→

MCQ 91 Mark

“No two electrons in the same atoms can have identical set of four quantum numbers”. This statement is known as

✓
Pauli’s exclusion principle
B
Hund’s rule
C
Aufbau rule
D
Heisenberg uncertainty principle

Answer

Correct option: A.

Pauli’s exclusion principle

View full question & answer→

MCQ 101 Mark

p-orbitals are ……. in shape.

A
spherical
✓
dumb bell
C
double dumb bell
D
diagonal

Answer

Correct option: B.

dumb bell

dumbbell

View full question & answer→

MCQ 111 Mark

The value of Plank’s constant is

✓
$6.626 \times 10^{-34} Js$
B
$6.023 \times 10^{-24} Js$
C
$1.667 \times 10^{-28} Js$
D
$6.626 \times 10^{-28} Js$

Answer

Correct option: A.

$6.626 \times 10^{-34} Js$

View full question & answer→

MCQ 121 Mark

The energy difference between the shells goes on ……….. when moved away from the nucleus.

A
Increasing
✓
decreasing
C
equalizing
D
static

Answer

Correct option: B.

decreasing

View full question & answer→

MCQ 131 Mark

What is the wave number of photon emitted during transition from orbit, $n=4$ to $n=2$ in hydrogen atom $\left[R_{ H }=109677 \ cm ^{-1}\right]$ ?

✓
$20564.44 \ cm ^{-1}$
B
$23032.17 \ cm ^{-1}$
C
$15354.78 \ cm ^{-1}$
D
$25225.7 \ cm ^{-1}$

Answer

Correct option: A.

$20564.44 \ cm ^{-1}$

$(a): n_1=2 ; n_2=4, Z=1$
$\overline{ v }=\frac{1}{\lambda}=R Z^2\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$
$\bar{v}=$ Wave number,
$\lambda=$ Wavelength,
$R=$ Rydberg constant,
$Z=$ Atomic number,
$n_1=$ Lower energy level,
$n_2=$ Higher energy level
$\bar{v}=109677 \times 1^2\left(\frac{1}{2^2}-\frac{1}{4^2}\right)$
$\bar{v}=109677 \times \frac{3}{16}=20564.44 \ cm ^{-1}$

View full question & answer→

MCQ 141 Mark

Which from following rule/principle states that "No two electrons in an atom can have the same set of four quantum numbers".

✓
Pauli's exclusion principle
B
Hund's rule
C
Aufbau rule
D
Heisenberg uncertainty principle

Answer

Correct option: A.

Pauli's exclusion principle

(a): According to Pauli's exclusion principle, no two electrons in an atom can have the same set of four quantum numbers.

View full question & answer→

MCQ 151 Mark

What is the mass in gram of 1 atom of an element if its atomic mass is $10 u$ ?

A
$2.06056 \times 10^{-22} g$
✓
$1.66056 \times 10^{-23} g$
C
$1.06056 \times 10^{-24} g$
D
$3.66056 \times 10^{-25} g$

Answer

Correct option: B.

$1.66056 \times 10^{-23} g$

(b): 1 mole of an element contains $6.022 \times 10^{23}$ atoms.
$6.022 \times 10^{23}$ atoms weigh $10 u$ or $10 g$.
$
\text { Mass of } 1 \text { atom }=\frac{10}{6.022 \times 10^{23}}=1.66056 \times 10^{-23} g
$

View full question & answer→

MCQ 161 Mark

Calculate the wave number of the photon emitted during transition from the orbit of $n=2$ to $n=1$ in hydrogen atom $\left[R_{ H }=109677 cm ^{-1}\right]$.

A
$27419.3 cm ^{-1}$
B
$109677.0 cm ^{-1}$
C
$12064.5 cm ^{-1}$
✓
$82257.8 cm ^{-1}$

Answer

Correct option: D.

$82257.8 cm ^{-1}$

(d) $: \nabla=\frac{1}{\lambda}=R Z^2\left(\frac{1}{n_1^2}-\frac{1}{m_2^2}\right)$
Here, $n_1=1: n_2=2, Z=1$
$\overline{ v }=R \times(1)^2\left(\frac{1}{ t ^2}-\frac{1}{2^2}\right)$
$\overline{ v }=\frac{3 R}{4}=\frac{3 \times 109677}{4}$ or $\overline{ v }=82257.8 cm ^{-1}$

View full question & answer→

MCQ 171 Mark

Find the number of unpaired electrons for copper in ground state configuration.

✓
1
B
2
C
3
D
4

Answer

Correct option: A.

(a) $: Cu (Z=29) \div[A r) 3 d^{10} 4 s^{13}$
\begin{tabular}{|l|l|l|l|l|} \hline 1 & 1 & 1 & 1 & 1 \\ \hline \end{tabular}
34 4s
It has one unpaired electron.

View full question & answer→

MCQ 181 Mark

Calculate the frequency if wavelength is $750 nm$.

A
$2 \times 10^{14} Hz$
✓
$4 \times 10^{14} Hz$
C
$6 \times 10^{15} Hz$
D
$8 \times 10^{15} Hz$

Answer

Correct option: B.

$4 \times 10^{14} Hz$

(b) : $\lambda=750 nm =750 \times 10^{-9} m , v =$ ?
$
u =\frac{c}{\lambda}=\frac{3 \times 10^8 ms ^{-1}}{750 \times 10^{-9} m }=4 \times 10^{14} Hz
$

View full question & answer→

MCQ 191 Mark

Calculate radius of third orbit of $He ^*$.

A
$52.9 pm$
B
$105.8 pm$
✓
$238.1 pm$
D
$423.2 pm$

Answer

Correct option: C.

$238.1 pm$

View full question & answer→

MCQ 201 Mark

Find the number of orbitals and maximum electrons respectively present in $M$ shell?

A
4,8
✓
9,18
C
16,32
D
1,2

Answer

Correct option: B.

9,18

(b): For $M$ shell, $n=3$
Maximum number of orbitals $=n^2=3^2=9$
Maximum number of electrons $=2 n^2=2 \times 9=18$

View full question & answer→

MCQ 211 Mark

What is the energy associated with first orbit of $Li ^{2+}$ $\left(R_H=2.18 \times 10^{-15} J \right)$ ?

✓
$-19.62 \times 10^{-18} J$
B
$-34.88 \times 10^{-16}$ )
C
$-2.18 \times 10^{-18}$ )
D
$-8.72 \times 10^{-18} J$

Answer

Correct option: A.

$-19.62 \times 10^{-18} J$

(a): $E_n=-R_H \frac{Z^2}{n^2}=\frac{-2.18 \times 10^{-18} \times Z^2}{n^2}$,
For $Li ^{2+} ; n=1, Z=3$
$
\begin{aligned}
F_n & =\frac{-2.18 \times 10^{-15} \times 3^2}{12} J =-2.18 \times 10^{-18} \times 9 J \\
& =-19,62 \times 10^{-15} J
\end{aligned}
$

View full question & answer→

MCQ 221 Mark

Match the following pairs. Species Number of electrons (A) O^(2-) (i) 18 (B) Li^(2+) (ii) 2 (C) He (iii) 10 (D) Ca^(++) (iv) 1

A
(A) - (i), (B) - (ii), (C) - (iv), (D) - (iii)
B
(A) - (ii), (B) - (iii), (C) - (i), (D) - (iv)
✓
(A) - (iii), (B) - (iv), (C) - (ii). (D) - (i)
D
(A) - (iv), (B) - (i), (C) - (iii), (D) - (ii)

Answer

Correct option: C.

(A) - (iii), (B) - (iv), (C) - (ii). (D) - (i)

(c) : Number of electrons in $O ^{2-}=8+2=10$
Number of electrons in $Li ^{2+}=3-2=1$
Number of electrons in $He =2$
Number of electrons in $Ca ^{2+}=20-2=18$

View full question & answer→

MCQ 231 Mark

The electronic configuration of $Ni^{2+}$ is _________ $($Atomic number of $Ni = 28)$

A
$[Ar] 4s^2 3d^6$
B
$[Ar] 4s^1 3d^8$
✓
$[Ar] 3d^8$
D
$[Ar] 4s^2 3d^8$

Answer

Correct option: C.

$[Ar] 3d^8$

View full question & answer→

MCQ 241 Mark

The ground state electronic configuration for chromium atom $(Z = 24)$ is

✓
$[Ar] 3d^5 4s^1$
B
$[Ar] 3d^4 4s^2$
C
$[Ar] 3d^8$
D
$[Ar] 4s^1 4p^5$

Answer

Correct option: A.

$[Ar] 3d^5 4s^1$

View full question & answer→

MCQ 251 Mark

For the electron present in 1 s orbital of helium atom, the correct set of values of quantum numbers is

✓
1, 0, 0, +1/2
B
1, 1, 0, +1/2
C
1, 1, 1, +1/2
D
2, 0, 0, +1/2

Answer

Correct option: A.

1, 0, 0, +1/2

View full question & answer→

MCQ 261 Mark

For 3d orbital, the values of n and l are ___________ respectively.

A
0, 3
✓
3, 2
C
3, 0
D
3, 3

Answer

Correct option: B.

3, 2

View full question & answer→

MCQ 271 Mark

The two electrons have the following set of quantum numbers:<br>$\begin{aligned}&\mathrm{P}=3,2,-2,+\frac{1}{2} \\& \mathrm{Q}=3,0,0,+\frac{1}{2}\end{aligned}
$<br>Which of the following statement is TRUE?

A
P and Q have same energy
✓
P has greater energy than Q
C
P has lesser energy than Q
D
P and Q represent same electron

Answer

Correct option: B.

P has greater energy than Q

View full question & answer→

MCQ 281 Mark

Which of the following pairs of d-orbitals will have electron density along the axis?

A
$d_{x y}, d_{x^2-y^2}$
B
$\mathrm{d}_{\mathrm{z}^2}, \mathrm{~d}_{\mathrm{xz}}$
C
$d_{x z^{\prime}} d_{y z}$
✓
$\mathrm{d}_{\mathrm{z}^2}, \mathrm{~d}_{\mathrm{x}^2-\mathrm{y}^2}$

Answer

Correct option: D.

$\mathrm{d}_{\mathrm{z}^2}, \mathrm{~d}_{\mathrm{x}^2-\mathrm{y}^2}$

View full question & answer→

MCQ 291 Mark

$p_{z^-}$ Orbital has ___________ nodal plane/planes.

A
zero
✓
one
C
two
D
three

Answer

Correct option: B.

one

View full question & answer→

MCQ 301 Mark

Which of the following is INCORRECT?

A
A nodal plane has $\psi^2$ very close to zero.
✓
The value of $\psi^2$ at any finite distance from the nucleus is always zero.
C
A boundary surface diagram enclosing 100 % probability density cannot be drawn.
D
A boundary surface diagram is a good representation of shape of an orbtial.

Answer

Correct option: B.

The value of $\psi^2$ at any finite distance from the nucleus is always zero.

View full question & answer→

MCQ 311 Mark

The maximum number of electrons in a subshell for which l = 3 is

✓
14
B
10
C
8
D
4

Answer

Correct option: A.

View full question & answer→

MCQ 321 Mark

The number of subshells in a shell is equal to$………...$

✓
$n$
B
$n^2$
C
$n – 1$
D
$l + 1$

Answer

Correct option: A.

$n$

View full question & answer→

MCQ 331 Mark

In a multi-electron atom, the energy of the orbital depends on two quantum numbers: _______________

A
n and ms
B
n and ml
C
ml and ms
✓
n and l

Answer

Correct option: D.

n and l

View full question & answer→

MCQ 341 Mark

An orbital is designated by ________ quantum numbers while an electron in an atom is designated by __________ quantum numbers.

A
two, three
B
three, two
C
four, two
✓
three, four

Answer

Correct option: D.

three, four

View full question & answer→

MCQ 351 Mark

The de Broglie wavelength associated with a particle of mass $10^{-6} \ kg$ moving with a velocity of $10 \ m s^{-1}$ is

A
$6.63 \times 10^{-22} m$
✓
$6.63 \times 10^{-29}m$
C
$6.63 \times 10^{-31} m$
D
$6.63 \times 10^{-34} m$

Answer

Correct option: B.

$6.63 \times 10^{-29}m$

View full question & answer→

MCQ 361 Mark

Which of the following is a hydrogen$-$like species?

A
$He^{2+}$
✓
$Be^{3+}$
C
$Li^+$
D
$H^+$

Answer

Correct option: B.

$Be^{3+}$

View full question & answer→

MCQ 371 Mark

The energy of electron in the $n^{th}$ Bohr orbit of $H-$atom is

A
$-\frac{2.18 \times 10^{-16}}{\mathrm{n}^2} \mathrm{~J}$
B
$-\frac{2.18 \times 10^{-18}}{n} \mathrm{~J}$
✓
$-\frac{2.18 \times 10^{-18}}{\mathrm{n}^2} \mathrm{~J}$
D
$-\frac{2.18 \times 10^{-16}}{\mathrm{n}} \mathrm{J}$

Answer

Correct option: C.

$-\frac{2.18 \times 10^{-18}}{\mathrm{n}^2} \mathrm{~J}$

View full question & answer→

MCQ 381 Mark

In hydrogen spectrum, the series of lines appearing in ultraviolet region of electromagnetic spectrum are called ………….

✓
Lyman series
B
Balmer series
C
Pfund series
D
Brackett series

Answer

Correct option: A.

Lyman series

View full question & answer→

MCQ 391 Mark

In the electromagnetic spectrum, the ultraviolet region is around $..........Hz.$

A
$10^6$
B
$10^{10}$
✓
$10^{16}$
D
$10^{26}$

Answer

Correct option: C.

$10^{16}$

View full question & answer→

MCQ 401 Mark

In vacuum, the speed of all types of electromagnetic radiation is equal to

A
$3.0 \times 10^6 \ m s^{-1}$
✓
$3.0 \times 10^8 \ m s^{-1}$
C
$3.0 \times 10^{10} \ m s^{-1}$
D
$3.0 \times 10^{12} \ m s^{-1}$

Answer

Correct option: B.

$3.0 \times 10^8 \ m s^{-1}$

View full question & answer→

MCQ 411 Mark

The number of electrons, protons and neutrons in $^{31}P^{3-}$ ion is respectively

A
$15, 15, 16$
B
$15, 16, 15$
✓
$18, 15, 16$
D
$15, 16, 18$

Answer

Correct option: C.

$18, 15, 16$

View full question & answer→

MCQ 421 Mark

The difference between $U^{235}$ and $U^{238}$ atoms is that $U^{238}$ contains

A
$3$ more protons
B
$3$ more protons and $3$ more electrons
C
$3$ more neutrons and $3$ more electrons
✓
$3$ more neutrons

Answer

Correct option: D.

$3$ more neutrons

View full question & answer→

MCQ 431 Mark

The isotopes of an element differ in

✓
the number of neutrons in the nucleus
B
the charge on the nucleus
C
the number of extra-nuclear electrons
D
both the nuclear charge and the number of extra-nuclear electrons

Answer

Correct option: A.

the number of neutrons in the nucleus

View full question & answer→

MCQ 441 Mark

Which of the following statements about the electron is INCORRECT?

A
It is a negatively charged particle.
✓
The mass of electron is equal to the mass of neutron.
C
It is a basic constituent of all atoms.
D
It is a constituent of cathode rays.

Answer

Correct option: B.

The mass of electron is equal to the mass of neutron.

View full question & answer→

Chemistry MCQ

Take a timed test