Atomic Structure

1

In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following interorbit jumps of the electron for Bohr orbits in an atom of hydrogen?

  1. 2 → 5
  2. 4 → 1
  3. 5 → 2
  4. 3 → 2
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2

Which of the following sets of quantum numbers is correct for an electron in 4f orbital?

  1. n = 4, l = 4, m = –4, s =-1/2
  2. n = 4, l = 3, m = +4, s =+1/2
  3. n = 3, l = 2, m = –2, s =+1/2
  4. n = 4, l = 3, m = +1, s =+1/2
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3

Which of the following statements in relation to the hydrogen atom is correct?

  1. 3s orbital is lower in energy than 3p orbital
  2. 3s, 3p and 3d orbitals all have the same energy
  3. 3s and 3p orbitals are of lower energy than 3d orbital
  4. 3p orbital is lower in energy than 3d orbital
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4

Consider the following nuclear reactions:

23892M → XYN + 242He  ;  XYN → ABL + 2β+

The number of neutrons in the element L is

  1. 146
  2. 144
  3. 142
  4. 140
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5

The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 metres per second is approximately (Planck's constant, h = 6.63 × 10–34 Js)

  1. 10–16 metres
  2. 10–31 metres
  3. 10–33 metres
  4. 10–25 metres
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6

Number of atoms in 558.5 gram Fe (atomic weight of Fe = 55.85 g mol–1) is

  1. twice that in 60 g carbon
  2. half that in 8 g He
  3. 6.023 × 1022
  4. 558.5 × 6.023 × 1023
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7

Which of the following is the energy of a possible excited state of hydrogen?

  1. - 6.8 eV
  2. - 3.4 eV
  3. + 6.8 eV
  4. + 13.6 eV
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8

Which one of the following groupings represents a collection of isoelectronic species? (At. nos.: Cs-55, Br-­35)

  1. Ca2+, Cs+, Br
  2. Na+, Ca2+, Mg2+
  3. N3-, F, Na+
  4. Be, Al3+, Cl
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9

If the principal quantum number n=6, the correct sequence of filling of electrons will be:

  1. ns→np→(n-1)d→(n-2)f
  2. ns→(n-2)f→(n-1)d→np
  3. ns→(n-1)d→(n-2)f→np
  4. ns→(n-2)f→np→(n-1)d
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10

A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of h/λ (where λ is wavelength associated with electron wave) is given by:

  1. 2meV
  2. √(meV)
  3. √(2meV)
  4. meV
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