1
MCQ (Single Correct Answer)

NEET 2017

Which one is the wrong statement ?
A
The uncertainty principle is

$$\Delta E \times \Delta t \ge {h \over {4\pi }}$$
B
Half filled and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement.
C
The energy of 2s-orbital is less than the energy of 2p-orbital in case of hydrogen like atoms.
D
de-Broglie's wavelength is given by

$$\lambda = {h \over {mv}}$$, where m = mass of the particle,

v $$=$$ group velocity of the particle.

Explanation

In the case of hydrogen type atoms, energy depends on the principal quantum number only. Therefore 2-s orbital will have energy equal to 2-p orbital.
2
MCQ (Single Correct Answer)

NEET 2016 Phase 1

Two electrons occupying the same orbital are distinguished by
A
azimuthal quantum number
B
spin quantum number
C
principal quantum number
D
magnetic quantum number

Explanation

For any two electrons occupying the same orbital values of n, l and ml are same but ms is different [ + $$1 \over 2$$ and - $$1 \over 2$$]
3
MCQ (Single Correct Answer)

NEET 2016 Phase 2

Which of the following pairs of d-orbitals will have electron density along the axes ?
A
$${d_{{z^2}}},\,\,{d_{xz}}$$
B
dxz,  $${d_{yz}}$$
C
$${d_{{z^2}}},\,\,{d_{{x^2} - {y^2}}}$$
D
$${d_{xy}},\,{d_{{x^2} - {y^2}}}$$

Explanation

dx2 - y2 and dz2 orbitals have electron density along the axes.
4
MCQ (Single Correct Answer)

NEET 2016 Phase 2

How many electrons can fit in the orbital for which n = 3 and $$l$$ = 1?
A
2
B
6
C
10
D
14

Explanation

For n = 3 and l = 1, the subshell is 3p and a particular 3p orbital can accodomodate only 2 electrons.

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