Structure of Atom

Consider two radiations of wavelengths 1. 1 = 2000 Å 2. 2 = 6000 Å The ratio of the energies of these two radiations ( E1E2 ) is (Nearest integer).

The surface of sodium metal is irradiated with radiation of wavelength x nm. The kinetic energy of ejected electrons is 2.8 10-20 J. The work function of sodium is 2.3 eV. The value of x is 102 nm. (Nearest integer) (Given : h = 6.6 10-34 J s; 1 eV = 1.6 10-19 J; c = 3.0 108 m s-1)

Two positively charged particles m1 and m2 have been accelerated across the same potential difference of 200 kV as shown below. [figure] [Given mass of m1 = 1 amu and m2 = 4 amu] The de Broglie wavelength of m1 will be x times of m2. The value of x is (nearest integer)

The hydrogen spectrum consists of several spectral lines in Lyman series (L1, L2, L3 ; L1 has lowest energy among Lyman series). Similarly it consists of several spectral lines in Balmer series (B1, B2, B3 ; B1 has lowest energy among Balmer lines). The energy of L1 is x times the energy of B1. The value of x is 10-1. (Nearest integer)

The energy of an electron in the first Bohr orbit of the H-atom is -13.6 eV. The magnitude of energy value of an electron in the first excited state of Be3+ is eV (nearest integer value).

Niobium (Nb) and ruthenium (Ru) have “x” and “y” number of electrons in their respective 4 d orbitals. The value of x+y is .

Based on Heisenberg's uncertainty principle, the uncertainty in the velocity of the electron to be found within an atomic nucleus of diameter 10-15 m is 109 ms-1 (nearest integer) [Given : mass of electron = 9.1 10-31 kg, Planck's constant (h) = 6.626 10-34 Js] (Value of = 3.14)

A hypothetical electromagnetic wave is shown below. [figure] The frequency of the wave is x 1019 Hz. x = (nearest integer)

Wavenumber for a radiation having 5800 Å wavelength is x 10 cm-1. The value of x is . (Integer answer)

Frequency of the de-Broglie wave of electron in Bohr's first orbit of hydrogen atom is 1013 Hz (nearest integer). [Given : RH (Rydberg constant) = 2.18 10-18 J, h (Planck's constant) = 6.6 10-34 J. s.]

For hydrogen atom, energy of an electron in first excited state is -3.4 eV. K.E. of the same electron of hydrogen atom is x eV. Value of x is 10-1 eV. (Nearest integer)

The value of Rydberg constant (RH) is 2.18 10-18 J. The velocity of electron having mass 9.1 10-31 kg in Bohr's first orbit of hydrogen atom = 105 ms-1 (nearest integer).

In an atom, total number of electrons having quantum numbers n = 4, |ml| = 1 and ms = - 12 is .

The de-Broglie's wavelength of an electron in the 4th orbit is 0. (a0 = Bohr's radius)

The maximum number of orbitals which can be identified with n = 4 and ml = 0 is .

The ionization energy of sodium in kJ mol-1, if electromagnetic radiation of wavelength 242 nm is just sufficient to ionize sodium atom is .

Number of spectral lines obtained in He+ spectra, when an electron makes transition from fifth excited state to first excited state will be

The number of electrons present in all the completely filled subshells having n = 4 and s = + 12 is . (Where n = principal quantum number and s = spin quantum number)

Total number of ions from the following with noble gas configuration is . Sr2+ (z = 38), Cs+ (z = 55), La2+ (z = 57), Pb2+ (z = 82), Yb2+ (z = 70) and Fe2+ (z = 26)