The basis of quantum mechanical model of an atom is

• angular momentum of electron

• quantum numbers

• dual nature of electron

• black body radiation

The quantum number which explains the line spectra observed as doublets in case of hydrogen and alkali metals and doublets and triplets in case of alkaline earth metals is

• spin

• azimuthal

• magnetic

• principal

133.

A compound absorbs light in the wavelength region 490-500 nm. Its complementary colour is

• red

• blue

• orange

• blue-green

Which of the following sets of quantum numbers is correct for an electron in 3d-orbital?

• n = 3; l = 2; m = -3; s = +$\frac{1}{2}$

• n = 3; l = 3; m = +3; s = -$\frac{1}{2}$

• n = 3; l = 2; m = -2; s = +$\frac{1}{2}$

• n = 3; l = 2; m = -3; s = -$\frac{1}{2}$

If the kinetic energy of a particle is reduced to half, de-Broglie wavelength becomes

• 2 times

• $\frac{1}{\sqrt{2}}$ times

• 4 times

• $\sqrt{2}$ times

In an atom the order of increasing energy of electrons with quantum numbers

(i) n=4, l=1      (ii) n=4, l=0     (iii) n=3, l=2 and (iv) n=3, l=1 is

• III < I <IV < II

• II < IV < I<III

• I <III <II <IV

• IV< II <III <I

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

• 3,1

• 1,2

• 3,0

• 2,1

The product of uncertainty in velocity and uncertainty in position of a micro particle of mass 'm' is not less than in which of the following?

• h × $\frac{3\mathrm{\pi }}{\mathrm{m}}$

• $\frac{\mathrm{h}}{3\mathrm{\pi }}$× m

• $\frac{\mathrm{h}}{4\mathrm{\pi }} \times \frac{1}{\mathrm{m}}$

• $\frac{\mathrm{h}}{4\mathrm{\pi }} \times \mathrm{m}$

2p orbitals have

• n = 1; l = 2

• n = 1; l = 0

• n = 2; l = 1

• n = 2; l = 0

Aufbau principle is not satisfied by

• Cr and Cl

• Cu and Ag

• Cr and Mg

• Cu and Na