## Fill in the Blanks

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The outermost electronic configuration of Cr is _______.
IIT-JEE 1994
The light radiations with discrete quantities of energy are called ______.
IIT-JEE 1993
Wave functions of electrons in atoms and molecules are called ______.
IIT-JEE 1993
The 2px, 2py and 2pz orbitals of atom have identical shapes but differ in their _____.
IIT-JEE 1993
The uncertainty principle and the concept of wave nature of matter were proposed by ______ and ______ respectively. (Hei...
IIT-JEE 1988
Elements of the same mass number but of different atomic numbers are known as ____.
IIT-JEE 1983
The mass of a hydrogen atom is ______ kg.
IIT-JEE 1982
Isotopes of an element differ in the number of ______ in their nuclei.
IIT-JEE 1982
When there are two electrons in the same orbital, they have _____ spins.
IIT-JEE 1982

## Numerical

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The maximum number of electrons that can have principal quantum number, n = 3, and spin quantum number, ms = − 1/2 , is...
IIT-JEE 2011
Find out the number of waves made by a Bohr electron in once complete revolution in its 3rd orbit?
IIT-JEE 1994
Not considering the electronic spin, the degeneracy of the second excited state( n = 3) of H atom is 9, while the degene...
In an atom, the total number of electrons having quantum numbers n = 4, |ml| = 1 and ms = –1/2 is
The atomic masses of He and Ne are 4 and 20 a.m.u., respectively. The value of the de Broglie wavelength of He gas at –7...
The work function ( φ ) of some metals is listed below. The number of metals which will show photoelectric effect when l...
IIT-JEE 2011

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P is the probability of finding the 1s electron of hydrogen atom in a spherical shell of infinitesimal thickness, dr, at...
Given that the abundances of isotopes 54Fe, 56Fe and 57Fe are 5%, 90% and 5%, respectively...
IIT-JEE 2009 Screening
The number of radial nodes of 3s and 2p orbitals are respectively
IIT-JEE 2005 Screening
The radius of which of the following orbit is same as that of the first Bohr's orbit of hydrogen atom?
IIT-JEE 2004 Screening
Rutherford's experiment, which established the nuclear model of the atom, used a beam of
IIT-JEE 2002 Screening
The wavelength associated with a golf ball weighing 200 g and moving at speed of 5 m/h is of the order
IIT-JEE 2001 Screening
The quantum numbers +1/2 and -1/2 for the electron spin represent
IIT-JEE 2001 Screening
The number of nodal planes in a px orbital is
IIT-JEE 2000 Screening
The electronic configuration of an element is 1s2, 2s2 2p6, 3s2 3p6 3d5, 4s1 This represents its...
IIT-JEE 2000 Screening
The orbital diagram in which the Aufbau principle is violated is
IIT-JEE 1998
For a d-electron the orbital angular momentum is
IIT-JEE 1997
The orbital angular momentum of an electron in 2s orbital is
IIT-JEE 1996
A 3p orbital has
IIT-JEE 1995 Screening
Which of the following does not characterise X-rays?
IIT-JEE 1992
Which of the following relates to photons both as wave motion and as a stream of particles?
IIT-JEE 1992
The correct ground state electronic configuration of chromium atom is
IIT-JEE 1989
The correct set of quantum numbers for the unpaired electron of chlorine atom is
IIT-JEE 1989
The triad of nuclei that is isotonic is
IIT-JEE 1988
The wavelength of a spectral line for an electronic transition is inversely related to :
IIT-JEE 1988
The outermost electronic configuration of the most electronegative element is
IIT-JEE 1988
Rutherford's alpha particle scattering experiment eventually led to the conclusion that:
IIT-JEE 1986
Which one of the following sets of quantum numbers represents an impossible arrangement?
IIT-JEE 1986
The ratio of the energy of a photon of 2000Å wavelength to that 4000Å radiation is
IIT-JEE 1986
Bohr Model can explain
IIT-JEE 1985
The radius of an atomic nucleus is of the order of
IIT-JEE 1985
Electromangnetic radiation with maximum wavelength is:
IIT-JEE 1985
The increasing order (lowest first) for the values of e/m (charges/mass) for electron (e), proton (p), neutron (n) and ...
IIT-JEE 1984
Correct set of four quantum numbers for the valence (outermost) electron of rubidium (Z = 37) is
IIT-JEE 1984
Which electronic level would allow the hydrogen atom to absorb a photon but not to emit a photon?
IIT-JEE 1984
Any p-orbital can accommodate upto
IIT-JEE 1983
The principal quantum number of an atom is related to the
IIT-JEE 1983
Rutherford's scattering experiment is related to the size of the
IIT-JEE 1983
Rutherford's experiment on scattering of $$\alpha-particles$$ showed for the first time that the atom has
IIT-JEE 1981
The number of neutrons in dipositive zinc ion with mass number 70 is
IIT-JEE 1979
The hydrogen like species Li2+ is in a spherically symmetric state S1 with one radial node. Upon absorbing light the ion...
IIT-JEE 2010
The hydrogen like species Li2+ is in a spherically symmetric state S1 with one radial node. Upon absorbing light the ion...
IIT-JEE 2010
The hydrogen like species Li2+ is in a spherically symmetric state S1 with one radial node. Upon absorbing light the ion...
IIT-JEE 2010
STATEMENT - 1 : The plot of atomic number (y-axis) versus number of neutrons (x-axis) for stable nuclei shows a curvatur...
IIT-JEE 2008
This question contains STATEMENT-1 (Assertion) and STATEMENT-2 (Reason) and has 4 choices (a), (b), (c), (d) out of whic...
IIT-JEE 2007
If the nitrogen atom has electronic configuration 1s7, it would have energy lower than that of the normal ground state c...
IIT-JEE 2002 Screening
The electrons, identified by quantum numbers n and l, (i) n = 4, l = 1, (ii) n = 4, l = 0, (iii) n = 3, l = 2 and (iv) n...
IIT-JEE 1999
ASSERTION: Nuclide $${}_{13}^{30}Al$$ is less stable than $${}_{20}^{40}Ca$$ REASON: Nuclides having odd number of proto...
IIT-JEE 1998
The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is [$$\alpha_0$$ is Bohr radius]
IIT-JEE 2012
Match the entries with column I with with the correctly related quantum number(s) in Column II. Column I (A) Orbital an...
IIT-JEE 2008
According to Bohr's theory En = Total energy, Kn = Kinetic Energy, Vn = Potential Energy, rn = Radius of nth orbit Mat...
IIT-JEE 2006

## MCQ (More than One Correct Answer)

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The sum of the number of neutrons and proton in the isotope of hydrogen is
IIT-JEE 1986
An isotone of $${}_{32}^{76}Ge$$ is
IIT-JEE 1984
Many elements have non-integral atomic masses because:
IIT-JEE 1984
When alpha particles are sent through a thin metal foil, most of them go straight through the foil because
IIT-JEE 1984
The energy of an electron in the first Bohr orbit of H atom is -13.6 eV. The possible energy value(s) of the excited sta...
IIT-JEE 1998
Which of the following statement(s) is (are) correct?
IIT-JEE 1998
Decrease in atomic number is observed during
IIT-JEE 1998
Ground state electronic configuration of nitrogen atom can be represented by
IIT-JEE 1999

## Subjective

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A ball of mass 100 g is moving with 100 ms-1. Find it's wavelength.
IIT-JEE 2004
Calculate the wave number for the shortest wavelength transition in the Balmer series of atomic hydrogen.
IIT-JEE 1996
Find the velocity (ms-1) of electron in first Bohr's orbit of radius a0. Also find the de Broglie's wavelength (in m). ...
IIT-JEE 2005
The Schrodinger wave equation for hydrogen atom is $$\psi = {1 \over {4\sqrt {2\pi } }}{\left( {{1 \over {{a_0}}}} \ri... IIT-JEE 2004 Wavelength of high energy transition of H-atoms is 91.2 nm. Calculate the corresponding wavelength of He atoms. IIT-JEE 2003 Consider the hydrogen atom to be a proton embedded in a cavity of radius a0 (Bohr radius) whose charge is neutralised by... IIT-JEE 1996 Iodine molecule dissociates into atoms after absorbing light of 4500 Å. If one quantum of radiation is absorbed by each ... IIT-JEE 1995 Give reasons why the ground state outermost electronic configuration of silicon is: ... IIT-JEE 1985 What is the maximum number of electrons that may be present in all atomic orbitals with principal quantum number 3 and a... IIT-JEE 1985 What transition in the hydrogen spectrum would have the same wavelength as the Balmer transition n = 4 to n = 2 of He+ s... IIT-JEE 1993 According to Bohr's theory, the electronic energy of hydrogen atom in the nth Bohr's orbit is given by$${E_n} = {{ - 21...
IIT-JEE 1990
The electron energy in hydrogen atom is given by E = (-21.7 $$\times$$ 10-12)/n2 ergs. Calculate the energy required to ...
IIT-JEE 1984
The energy of the electron in the second and the third Bohr's orbits of the hydrogen atom is -5.42 $$\times$$ 10-12 erg ...
IIT-JEE 1981
Calculate the energy required to excite one litre of hydrogen gas at 1 atm and 298 K to the first excited state of atomi...
IIT-JEE 2000
Calculate the wavelength in Angstrom of the photon that is emitted when an electron in the Bohr orbit, n = 2 returns to ...
IIT-JEE 1982
Naturally occurring boron consists of two isotopes whose atomic weighs are 10.01 and 11.01. The atomic weight of natural...
IIT-JEE 1978
Estimate the difference in energy between 1st and 2nd Bohr orbit for a hydrogen atom. At what minimum atomic number, a t...
IIT-JEE 1993

## True or False

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In a given electric field, $$\beta-particles$$ are deflected more than $$\alpha-particles$$ in spite of \alpha-partic...
IIT-JEE 1993
The electron density in the XY plane in 3dx2 - y2 orbital is zero
IIT-JEE 1986
Gamma rays are electromagnetic radiations of wavelengths of 10-6 to 10-5 cm
IIT-JEE 1983
The energy of the electron in the 3d-orbital is less than that in the 4s-orbital in the hydrogen atom.
IIT-JEE 1983
The outer electronic configuration of the ground state chromium atom is 3d4 4s2
IIT-JEE 1982

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