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Number of unpaired electrons in 1s² 2s² 2p³ is -
1. 2
2. 0
3. 3
4. 1

With a certain exciting radiation of a particular frequency, to which hydrogen atoms are exposed, the maximum number of spectral lines obtainable in the emission is 15. The uppermost energy level to which the electron is excited is 
1. 4
2. 5
3. 6
4. 7

Consider an electron which is brought close to the nucleus of the atom from an infinite distance, the energy of the electron-nucleus system:
1. Increases
2. Decreases
3. Remains the same
4. None of these

Using radiation of wavelength 3500 Å, it is observed that the maximum kinetic energy of the emitted photoelectrons is 1.6 eV for potassium. Calculate the work function of the metal. [h=6.626 x 10^-34 Js, 1 eV=1.6 x 10^-19 J]
1. 3 eV
2. 2.5 eV
3. 3.5 eV
4. 2 eV

The mass ratio of photons corresponding to the first lines of the Lymann and the Balmer series of the atomic spectrum of hydrogen is :

Which of the following has the maximum number of  unpaired electons-
1. Mg²⁺
2. Ti³⁺
3. V³⁺
4. Fe²⁺

There are three energy levels in an atom. How many spectral lines are possible in its emission spectra?
1. One
2. Two
3. Three
4. Four

 3p orbital has -
1. Two spherical nodes
2. Two non-spherical nodes
3. One spherical and one non-spherical node
4. One spherical and two non-spherical nodes

The transition in the He⁺ ion in the balmer series that would have the same wave number as the first Lyman line in the hydrogen spectrum is-

The number of electrons in  ₁₉ K with quantum numbers n=3; l=0 is/are
1. 2
2. 1
3. 4
4. 3

For d-electron, the orbital angular momentum is 
1. $\sqrt{6}\frac{h}{2\mathrm{\pi }}$
2. $\sqrt{2}\frac{h}{2\mathrm{\pi }}$
3. $\frac{h}{2\mathrm{\pi }}$
4. $\frac{2h}{\mathrm{\pi }}$

The number of orbitals that are possible at the L-energy level is
1. 2
2. 4
3. 6
4. 1

Which of the following pairs of d-orbitals will have electron density along the axes?
1. d_z²,d_xz
2. d_xz,d_yz
3. d_z²,d_x²-y²
4. d_xy,d_x²-y²

Magnetic moment of 2.83 BM is given by which of the following ions?
(At no: Ti=22; Cr=24; Mn=25; Ni=28)
1. Ti³⁺                 
2. Ni²⁺
3. Cr³⁺                 
4. Mn²⁺

The measurement of the electron position is associated with an uncertainty in momentum which is equal to 1x10^-18 g cm s^-1. The uncertainty in velocity of the electron will be:
(mass of an electron is 9 x 10^-28 g)
1. 1 x 10⁹ cm s^-1                     
2. 1 x 10⁶ cm s^-1
3. 1 x 10⁵ cm s^-1                     
4. 1 x 10¹¹ cm s^-1

Which one of the following ions is the most stable in aqueous solution?
(1) Cr³⁺                         
(2) V³⁺
(3) Ti3+                         
(4) Mn³⁺
(At no. Ti=22, V=23, Cr=24, Mn=25)

 The largest de Broglie wavelength among the following (all have equal velocity) is: 
1.  ${\mathrm{CO}}_2$ molecule
2.  ${\mathrm{NH}}_3$ molecule
3.  Electron
4.  Proton

 $\sqrt{\mathrm{V}}$on two particles A and B are plotted against de-Broglie wavelengths. Where V is the potential on the particles. Which of the following relation is correct about the mass of particles?
                             
1.  ${\mathrm{m}}_{\mathrm{A}}={\mathrm{m}}_{\mathrm{B}}$
2.  ${\mathrm{m}}_{\mathrm{A}}>{\mathrm{m}}_{\mathrm{B}}$
3.  ${\mathrm{m}}_{\mathrm{A}}<{\mathrm{m}}_{\mathrm{B}}$
4.  ${\mathrm{m}}_{\mathrm{A}}\le {\mathrm{m}}_{\mathrm{B}}$

The excited state of an H atom emits a photon of wavelength $\mathrm{\lambda }$ and returns to the ground state. The principal quantum number of the excited state is given by:
1.  $\sqrt{\mathrm{\lambda R}\left(\mathrm{\lambda R}-1\right)}$
2.  $\sqrt{\frac{\mathrm{\lambda R}}{\left(\mathrm{\lambda R}-1\right)}}$
3.  $\sqrt{\mathrm{\lambda R}\left(\mathrm{\lambda R}+1\right)}$
4.  $\sqrt{\frac{\left(\mathrm{\lambda R}-1\right)}{\mathrm{\lambda R}}}$

Which of the following set of quantum number is not valid
1. n = 1 , $\mathcal{l}$ = 2
2. n=2, m = 1
3. n =3, $\mathcal{l}$ = 0
4. n = 4, $\mathcal{l}$ = 2