class 11 chemistry mcq

The two electrons in an orbit are distinguished by

• principal quantum number

• angular momentum quantum number

• spin quantum number

• magnetic quantum number

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:

• 518 nm

• 1035 nm

• 325 nm

• 743 nm

When the angular momentum number ,l=1,the shape of the orbital will be

• spherical

• dumbbell

• double dumbbell

• diffused

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

• 12 and 4

• 12 and 5

• 16 and 4

• 16 and 5

A body of mass 10 mg is moving with a velocity of 100 ms-1. The wavelength of de-Broglie wave associated with it would be (Note: h = 6.63 × 10-34 Js)

• 6.63 × 10-37 m

• 6.63 × 10-31 m

• 6.63 × 10-34 m

• 6.63 × 10-35 m

Which of the following statements does not form a part of Bohrs model of hydrogen atom?

• a) Energy of the electrons in the orbit is quantised

• The electron in the orbit nearest the nucleus has the lowest energy

• Electrons revolve in different orbits around the nucleus.

• The position and velocity of the electrons in the orbit cannot be determined simultaneously

A sub-shell with n = 6 , l = 2 can accommodate a maximum of

• 12 electrons

• 36 electrons

• 10 electrons

• 72 electrons

Maximum number of electrons in a sub-shell can be

• 4l + 2

• 4l –2

• 2n2

• 2l + 1

The ground state electronic configuration of Fe3+ is

• [Ar]3d4 4s1

• [Ar]3d3 4s2

• [Ar]3d5 4s0

• [Ar]3d6 4s2

Which of the following has non-spherical shells of electron

• He

• B

• Be

• Li