Which of the following has the largest number of atoms? from Che

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 Multiple Choice QuestionsMultiple Choice Questions

241.

What is the wavelength associated with a tennis ball of mass 103 g and travelling at a velocity of 6.626 ms-1 ?[h = 6.626 x 10-34 Js-1].

  • 10-34 m

  • 10-31 m

  • 6.626 m

  • 6.626 × 10-31 m


242.

What is the energy required to move the electron from ground state of H atom to the first excited state? Given that the ground state energy of H atom is 13.6 eV and that the energy En of an electron in nth orbital of an atom or ion of atomic number Z is given by the equation En= - (13.6Z2 /n2).

  • 13.6 eV

  • 3.4 eV

  • 10.2 eV

  • -10.2 eV


243.

Which electron orbitals are designated by
(i) n = 2, l = 1, m = 0;
(ii) n = 3, l=2, m = O;
(iii) n=4, l = 2, m=1 and
(iv) n = 5, l=3, m=3 respectively?

  • 2p, 3d, 4d and 5f, respectively

  • 2p, 3d, 4d and 5d, respectively

  • 2p, 3d, 4f and 5f, respectively

  • 2p, 3p, 4d and 5f, respectively


244.

Which one of the following represents the correct ratio of the energy of electron in ground state of H atom to that of the electron in the first excited state of Li+?

  • 4 : 9

  • 9 : 4

  • 1 : 4

  • 4 : 1


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245.

Which one of the following complexes is an outer orbital complex?

(Atomic number of Mn = 25; Fe = 26; Co = 27 and Ni = 28)

  • [Fe(CN)6]4-

  • [Mn(CN)6]4-

  • [Co(NH3)6]3+

  • [Ni(NH3)6]2+


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246.

Which of the following has the largest number of atoms?

  • 0.5 gm atom of Cu

  • 0.635 gm of Cu

  • 0.25 moles of Cu atoms

  • 1 gm of Cu


A.

0.5 gm atom of Cu

The largest number of atoms can be calculated as-

(a) 0.5 gm atoms of Cu-

Cu = 0.5 × 6.023 × 1023

    = 3.011 × 1023 Cu atoms

(b) 0.635 gm of Cu = 0.63563.5 × 6.023 × 1023

                            = 6.023 × 1021 Cu atoms

(c) 0.25 moles of Cu = 0.25 × 0.623 × 1023

                              = 1.5 × 1023 Cu atoms

(d) 1 gm Cu = 163.5 × 6.023 × 1023 

                  = 9.48 × 1021 Cu atoms

Therefore, 0.5 gm atom of Cu has maximum number of Cu atoms.


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247.

Which of the following will violate Pauli's exclusion principle?

  • Both (a) and (b)

  • None of the above


248.

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

  • 12

  • 127

  • 49

  • 275


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249.

Which pair of elements has same chemical properties?

  • 13, 22

  • 3, 11

  • 4, 24

  • 2, 4


250.

The wave number of hydrogen atom in Lyman series is 82200 cm-1. The electron goes from

  • n3 → n2

  • n2 → n1

  • n4 → n3

  • None of these


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