## MCQ (Single Correct Answer)

Which one of the following sets of ions represents a collection of isoelectronic species?
(Given : Atomic Number : $$\mathrm{F:9,Cl:17,Na=11,Mg=12,Al=...

Arrange the following orbitals in decreasing order of energy.
A. $\mathrm{n}=3, \mathrm{l}=0, \mathrm{~m}=0$
B. $\mathrm{n}=4, \mathrm{l}=0, \mathrm{~...

$$\mathrm{Nd^{2+}}$$ = __________

Which transition in the hydrogen spectrum would have the same wavelength as the Balmer type transition from $$\mathrm{n=4}$$ to $$\mathrm{n}=2$$ of $$...

Maximum number of electrons that can be accommodated in shell with $n=4$ are:

The wave function $(\Psi)$ of $2 \mathrm{~s}$ is given by
$$
\Psi_{2 \mathrm{~s}}=\frac{1}{2 \sqrt{2 \pi}}\left(\frac{1}{a_0}\right)^{1 / 2}\left(2-\f...

The shortest wavelength of hydrogen atom in Lyman series is $$\lambda$$. The longest wavelength is Balmer series of He$$^+$$ is

The radius of the $$\mathrm{2^{nd}}$$ orbit of $$\mathrm{Li^{2+}}$$ is $$x$$. The expected radius of the $$\mathrm{3^{rd}}$$ orbit of $$\mathrm{Be^{3+...

The number of s-electrons present in an ion with 55 protons in its unipositive state is

The magnetic moment of a transition metal compound has been calculated to be 3.87 B.M. The metal ion is

It is observed that characteristic X-ray spectra of elements show regularity. When frequency to the power "n" i.e. $${v^n}$$ of X-rays emitted is plot...

Given below are the quantum numbers for 4 electrons.
A. $$\mathrm{n}=3,l=2, \mathrm{~m}_{1}=1, \mathrm{~m}_{\mathrm{s}}=+1 / 2$$
B. $$\mathrm{n}=4,l=1...

Given below are two statements: One is labelled as Assertion $$\mathbf{A}$$ and the other is labelled as Reason $$\mathbf{R}$$
Assertion $$\mathbf{A}$...

Identify the incorrect statement from the following.

The correct decreasing order of energy for the orbitals having, following set of quantum numbers :
(A) n = 3, l = 0, m = 0
(B) n = 4, l = 0, m = 0
(C)...

Outermost electronic configurations of four elements A, B, C, D are given below :
(A) $$3 s^{2}$$
(B) $$3 s^{2} 3 p^{1}$$
(C) $$3 s^{2} 3 p^{3}$$
(D) ...

Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Energy of $$2 \mathrm{s}$$ orbital ...

Which of the following sets of quantum numbers is not allowed?

The number of radial nodes and total number of nodes in 4p orbital respectively are :

Which of the following is the correct plot for the probability density $${\psi ^2}$$ (r) as a function of distance 'r' of the electron from the nucleu...

Which of the following statements are correct?
(A) The electronic configuration of Cr is [Ar] 3d5 4s1.
(B) The magnetic quantum number may have a nega...

Consider the following statements :
(A) The principal quantum number 'n' is a positive integer with values of 'n' = 1, 2, 3, ...
(B) The azimuthal qua...

The number of radial and angular nodes in 4d orbital are, respectively

If the radius of the 3rd Bohr's orbit of hydrogen atom is r3 and the radius of 4th Bohr's orbit is r4. Then :...

The minimum energy that must be possessed by photons in order to produce the photoelectric effect with platinum metal is :
[Given : The threshold freq...

The pair, in which ions are isoelectronic with AI3+ is :

The energy of one mole of photons of radiation of wavelength 300 nm is (Given : h = 6.63 $$\times$$ 10$$-$$34 J s, NA = 6.02 $$\times$$ 1023 mol$$-$$1...

Consider the following pairs of electrons
(A) (a) n = 3, $$l$$ = 1, m1 = 1, ms = + $${1 \over 2}$$
(b) n = 3, 1 = ...

Given below are two statements.Statement I : According to Bohr's model of an atom, qualitatively the magnitude of velocity of electron increases with ...

If the Thompson model of the atom was correct, then the result of Rutherford's gold foil experiment would have been :

Given below are two statements :Statement I : Rutherford's gold foil experiment cannot explain the line spectrum of hydrogen atom.Statement II : Bohr'...

The spin only magnetic moments (in BM) for free Ti3+, V2+ and Sc3+ ions respectively are(At.No. Sc : 21, Ti : 22, V : 23)...

Outermost electronic configuration of a group 13 element, E, is 4s2, 4p1. The electronic configuration of an element of p-block period-five placed dia...

Given below are two statements :Statement I : Bohr's theory accounts for the stability and line spectrum of Li+ ion.Statement II : Bohr's theory was u...

The ionic radius of Na+ ions is 1.02 $$\mathop A\limits^o $$. The ionic radii (in $$\mathop A\limits^o $$) of Mg2+ and Al3+, respectively, are ...

A certain orbital has no angular nodes and two radial nodes. The orbital is :

What is the spin-only magnetic moment value (BM) of a divalent metal ion with atomic number 25, in it's aqueous solution?

Which of the following forms of hydrogen emits low energy $$\beta$$- particles?

The orbital having two radial as well as two angular nodes is :

The plots of radial distribution functions for various orbitals of hydrogen atom against 'r' are given below :
The correct plot for 3s orbital is :...

In which of the following pairs, the outer most electronic configuration will be the same?

According to Bohr's atomic theory :(A) Kinetic energy of electron is $$ \propto {{{Z^2}} \over {{n^2}}}$$.(B) The product of velocity (v) of electron ...

The correct statement about probability density (except at infinite distance from nucleus) is :

The difference between the radii of 3rd and 4th
orbits of Li2+ is R1
. The difference between the
radii of 3rd and 4th orbits of He+ is
$$\Delta $$R2 ...

The correct electronic configuration and spin-only magnetic moment (BM) of Gd3+ (Z = 64),
respectively, are

In the sixth period, the orbitals that are filled are :

The shortest wavelength of H atom in the
Lyman series is $$\lambda $$1. The longest wavelength in
the Balmar series of He+ is :

The region in the electromagnetic spectrum
where the Balmar series lines appear is :

The number of subshells associated with n = 4
and m = –2 quantum numbers is

The figure that is not a direct manifestation of
the quantum nature of atoms is :

The de Broglie wavelength of an electron in the
4th Bohr orbit is :

The radius of the second Bohr orbit, in terms
of the Bohr radius, a0, in Li2+ is :

Hydrogen has three isotopes (A), (B) and (C).
If the number of neutron(s) in (A), (B) and (C)
respectively, are (x), (y) and (z), the sum of (x),
(y) ...

For the Balmer series in the spectrum of H atom,
$$\overline \nu = {R_H}\left\{ {{1 \over {n_1^2}} - {1 \over {n_2^2}}} \right\}$$, the correct stat...

The number of orbitals associated with quantum number n = 5, ms = +$${1 \over 2}$$ is :

The electrons are more likely to be found :
...

The group number, number of valence electrons, and valency of an element with atomic number 15,
respectively, are:

The ratio of the shortest wavelength of two spectral series of hydrogen spectrum is found to be about 9. The
spectral series are :

Consider the hydrated ions of Ti2+, V2+, Ti3+, and Sc3+. The correct order of their spin-only magnetic
moments is : ...

The isoelectronic set of ions is :

The graph between $${\left| \psi \right|^2}$$ and r (radial distance) is shown below. This represents :
...

Which one of the following about an electron
occupying the 1s orbital in a hydrogen atom is
incorrect ? (The Bohr radius is represented
by a0)...

For any given series of spectral lines of atomic
hydrogen, let $$\Delta \mathop v\limits^\_ = $$ $$\Delta {\overline v _{\max }} - \Delta {\overline ...

If p is the momentum of the fastest electron
ejected from a metal surface after the irradiation
of light having wavelength $$\lambda $$, then for 1.5 ...

The quantum number of four electrons are given below :
n = 4, l = 2, ml =–2, ms = –1/2
n = 3, l = 2, ml = 1, ms = +1/2
n = 4, l = 1, ml = 0, ms = +1/2...

If the de Broglie wavelength of the electron in nth Bohr orbit in a hydrogenic atom is equal to 1.5 $$\pi $$a0 (a0 is Bohr radius), then the value of ...

The upper stratosphere consisting of the ozone layer protects us from sun's radiation that falls in the wavelength region of -

What is the work function of the metal if the light of wavelength 4000$$\mathop A\limits^ \circ $$ generates photoelectrons of velocity 6 $$ \times $...

The de Broglie wavelength ($$\lambda $$) associated with a photoelectron varies with the frequency (v) of the incident radiation as, [v0 is threshold ...

Heat treatment of muscular pain involves radiation of wavelength of about 900 nm. Which spectral line of H atom is suitable for this purpose?
[RH = 1 ...

The ground state energy of hydrogen atom is – 13.6 eV. The energy of second excited state of He+ ion in eV is :

Which of the following combination of statements is true regarding the interpretation of the atomic orbitals ?
(a) An electron in an orbital of high ...

The highest value of the calculated spin- only magnetic moment (in BM) among all the transition metal complexes is :

For emission line of atomic hydrogen from ni = 8 to nf = n, the plot of wave number $$\left( {\overline v } \right)$$ against $$\left( {{1 \over {{n^2...

Which of the following statements is false ?

The de-Broglie's wavelength of electron present in first Bohr orbit of 'H' atom is :

Ejection of the photoelectron from metal in the photoelectric experiment can be stopped by applying 0.5 V when the radiation of 250 nm is used. The wo...

The electron in the hydrogen atom undergoes transition from higher orbitals
to orbital of radius 211.6 pm. This transition is associated with :

If the shortest wavelength in Lyman series of hydrogen atom is A, then the longestwavelength in Paschen series of He+ is :

The radius of the second Bohr orbit for hydrogen atom is:
(Planck’s Const. h = 6.6262 × 10-34 Js; mass of electron = 9.1091 × 10-31 kg; charge of elec...

The group having isoelectronic species is:

The total number of orbitals associated with the principal quantum number 5 is :

A stream of electrons from a heated filament was passed between two charged plates kept at a potential
difference V esu. If e and m are charge and mas...

Which of the following is the energy of a possible excited state of hydrogen?

The correct set of four quantum numbers for the valence elections of rubidium atom (Z= 37) is:

Energy of an electron is given by $$E = - 2.178 \times {10^{ - 18}}J\left( {{{{Z^2}} \over {{n^2}}}} \right)$$. Wavelength of light required to excit...

The electrons identified by quantum numbers n and l :
(a) n = 4, $$l$$ = 1
(b) n = 4, $$ l$$ = 0
(c) n = 3, $$l$$ = 2
(d) n = 3, $$l$$ = 1
Can be plac...

A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emissions is at
680 nm, the other is at :

The energy required to break one mole of Cl–Cl bonds in Cl2 is 242 kJ mol–1. The longest
wavelength of light capable of breaking a single Cl – Cl bond...

Ionisation energy of He+ is 19.6 x 10–18 J atom–1. The energy of the first stationary state (n = 1) of Li2+ is...

Calculate the wavelength (in nanometer) associated with a proton moving at 1.0 x 103 ms−1
(Mass of proton = 1.67 $$\times$$ 10-27 kg and h = 6.63 $$...

In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainity
with which the position of the electron can be locate...

Which one of the following constitutes a group of the isoelectronic species?

The ionization enthalpy of hydrogen atom is 1.312 × 106 J mol−1. The energy required to excite the
electron in the atom from n = 1 to n = 2 is ...

Which of the following sets of quantum numbers represents the highest energy of an atom?

According to Bohr's theory, the angular momentum of an electron in 5th orbit is

Uncertainty in the position of an electron (mass = 9.1 $$\times$$ 10-31 kg) moving with a velocity 300 ms-1, accurate upto 0.001% will be (h = 6.63 $$...

Which of the following sets of ions represents a collection of isoelectronic species?

Of the following sets which one does NOT contain isoelectronic species?

In a multi-electron atom, which of the following orbitals described by the three quantum members will have the same energy in the absence of magnetic ...

Pick out the isoelectronic structure from the following :
$$\eqalign{
& \left( i \right)\,\,\,\,\,\,C{H_3}^ + \cr
& \left( {ii} \right...

Which of the following sets of quantum numbers is correct for an electron in 4f orbital?

Consider the ground state of Cr atom (Z = 24). The number of electrons with the azimuthal quantum numbers, l = 1 and 2 are respectively

The wavelength of the radiation emitted when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.09...

Which one of the following sets of ions represents the collection of isoelectronic species? (Atomic nos. : F = 9, Cl = 17, Na = 11, Mg = 12, Al = 13, ...

The number of d-electrons retained in Fe2+ (At no of Fe = 26) ion is

The orbital angular momentum for an electron revolving in an orbit is given by $$\sqrt {l(l + 1)} {h \over {2\pi }}$$. This momentum for an s-electron...

Which one of the following groupings represents a collection of isoelectronic species? (At. nos. : Cs : 55, Br : 35)

In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the elect...

The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 meters per second is approximately

Uncertainty in position of a minute particle of mass 25 g in space is 10-5 m. What is the uncertainty in its velocity (in ms-1) (h = 6.6 $$\times$$ 10...

In a hydrogen atom, if energy of an electron in ground state is -13.6 eV, then that in the 2nd excited state is

## Numerical

Electrons in a cathode ray tube have been emitted with a velocity of 1000 m s$$^{-1}$$. The number of following statements which is/are $$\underline {...

The energy of one mole of photons of radiation of frequency $$2 \times 10^{12} \mathrm{~Hz}$$ in $$\mathrm{J} ~\mathrm{mol}^{-1}$$ is ___________. (Ne...

Assume that the radius of the first Bohr orbit of hydrogen atom is 0.6 $$\mathrm{\mathop A\limits^o }$$. The radius of the third Bohr orbit of He$$^+$...

The number of given orbitals which have electron density along the axis is _________
$$\mathrm{p_x,p_y,p_z,d_{xy},d_{yz},d_{xz},d_{z^2},d_{x^2-y^2}}$$...

If wavelength of the first line of the Paschen series of hydrogen atom is 720 nm, then the wavelength of the second line of this series is _________ n...

The minimum uncertainty in the speed of an electron in an one dimensional region of length $$2 \mathrm{a}_{\mathrm{o}}$$ (Where $$\mathrm{a}_{\mathrm{...

If the wavelength for an electron emitted from $$\mathrm{H}$$-atom is $$3.3 \times 10^{-10} \mathrm{~m}$$, then energy absorbed by the electron in its...

Consider an imaginary ion $${ }_{22}^{48} \mathrm{X}^{3-}$$. The nucleus contains '$$a$$'% more neutrons than the number of electrons in the ion. The ...

The wavelength of an electron and a neutron will become equal when the velocity of the electron is $$x$$ times the velocity of neutron. The value of $...

When the excited electron of a H atom from n = 5 drops to the ground state, the maximum number of emission lines observed are _____________.

If the work function of a metal is 6.63 $$\times$$ 10$$-$$19J, the maximum wavelength of the photon required to remove a photoelectron from the metal ...

Consider the following set of quantum numbers.
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If the uncertainty in velocity and position of a minute particle in space are, 2.4 $$\times$$ 10$$-$$26 (m s$$-$$1) and 10$$-$$7 (m) respectively. The...

The longest wavelength of light that can be used for the ionisation of lithium atom (Li) in its ground state is x $$\times$$ 10$$-$$8 m. The value of ...

A 50 watt bulb emits monochromatic red light of wavelength of 795 nm. The number of photons emitted per second by the bulb is x $$\times$$ 1020. The v...

The value of magnetic quantum number of the outermost electron of Zn+ ion is ______________.

Ge(Z = 32) in its ground state electronic configuration has x completely filled orbitals with ml = 0. The value of x is ___________.

The number of photons emitted by a monochromatic (single frequency) infrared range finder of power 1 mW and wavelength of 1000 nm, in 0.1 second is x ...

The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is equal to $${{{h^2}} \over {xma_0^2}}$$. The value of 10x is _________...

A metal surface is exposed to 500 nm radiation. The threshold frequency of the metal for photoelectric current is 4.3 $$\times$$ 1014 Hz. The velocity...

An accelerated electron has a speed of 5 $$\times$$ 106 ms$$-$$1 with an uncertainty of 0.02%. The uncertainty in finding its location while in motion...

A source of monochromatic radiation of wavelength 400 nm provides 1000 J of energy in 10 seconds. When this radiation falls on the surface of sodium, ...

Number of electrons that Vanadium (Z = 23) has in p-orbitals is equal to _____________

The wavelength of electrons accelerated from rest through a potential difference of 40 kV is x $$\times$$ 10$$-$$12 m. The value of x is ___________. ...

The Azimuthal quantum number for the valence electrons of Ga+ ion is ___________.(Atomic number of Ga = 31)

In the ground state of atomic Fe(Z = 26), the spin-only magnetic moment is ____________ $$\times$$ 10$$-$$1 BM. (Round off to the Nearest Integer). [G...

A certain orbital has n = 4 and mL = $$-$$3. The number of radial nodes in this orbital is ____________. (Round off to the Nearest Integer)....

The number of orbitals with n = 5, m1 = +2 is ___________. (Round off to the Nearest Integer).

When light of wavelength 248 nm falls on a metal of threshold energy 3.0 eV, the de-Broglie wavelength of emitted electrons is _______$$\mathop A\limi...

A ball weighing 10 g is moving with a velocity of 90 ms$$-$$1. If the uncertainty in its velocity is 5%, then the uncertainty in its position is _____...

A proton and a Li3+ nucleus are accelerated by the same potential. If $$\lambda _{Li}$$ and $$\lambda _p$$ denote the
de Broglie wavelengths of Li3+ a...

The work function of sodium metal is
4.41 $$ \times $$ 10–19 J. If photons of wavelength 300 nm
are incident on the metal, the kinetic energy of
the e...