561.

In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainty with which the position of the electron can be located is

(Given, h= 6.6 x 10^-34 kg m² s^-1, mass of electron e_m = 9.1 x 10^-31 kg)

• 215 x 10^-3 m

• 2.78 x 10^-3 m

• 1.92 x 10^-3 m

• 3.24 x 10^-3 m

Maximum number of electrons in a subshell of an atom determined by the following?

• 4l + 2

• 2n²

• 4l - 2

• 2l + 1

Which one of the following sets of quantum numbers represents the highest energy level in an atom?

• n = 4; l = 0; m = 0; s = +$\frac{1}{2}$

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

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

• n = 3; l = 0; m = 0; s = +$\frac{1}{2}$

The ratio of the difference in energy between the first and the second Bohr orbit to that between the second and the third Bohr orbit is

• $\frac{1}{2}$

• $\frac{1}{3}$

• $\frac{4}{9}$

• $\frac{27}{5}$

Which of the following has the maximum number of unpaired electrons?

• V³⁺

• Fe²⁺

• Mn²⁺

• Cu⁺

The geometry of XeF₆ is

• planar hexagon

• regular octahedron

• distorted octahedron

• square bipyramid

A 600 W mercury lamp emits monochromatic radiation of wavelength 331.3 nm. How many photons are emitted from the lamp per second? (h = 6.626x 10^-34 J-s; velocity of light = 3x10⁸ ms^-1)

• 1 x 10¹⁹

• 1 x 10²⁰

• 1 x 10²¹

• 1 x 10²³

In the electronic structure of H₂SO₄ , the total number of unshared electrons is

• 20

• 16

• 12

• 8

Which of the following relation is correct ?

• I^st IE of C > I^st IE of B

• I^st IE of C < I^st IE of B

• II^nd IE of C > II^nd IE of B

• Both (b) and (c)

Considering H₂O as weak field ligand, the number of unpaired electrons in [Mn(H₂O)₆] will be (Atomic number of Mn = 25)

• five

• two

• four

• three