The radius of hydrogen atom in the ground state is 0.53 Å. The radius of Li²⁺ ion (atomic number = 3) in a similar state is :

• 0.176 Å

• 0.30 Å

• 0.53 Å

• 1.23 Å

The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.097 × 10⁷ m^-1)

• 91 nm

• 192 nm

• 406 nm

• 9.1 × 10^-8 nm

The radioactive isotope ${}_{27}{}^{60}\mathrm{Co}$ which is used in the treatment of cancer can be made by (n, p) reaction. For this reaction the target nucleus is

• ${}_{28}{}^{59}\mathrm{Ni}$

• ${}_{27}{}^{59}\mathrm{Co}$

• ${}_{28}{}^{60}\mathrm{Ni}$

• ${}_{27}{}^{60}\mathrm{Co}$

The energy of second Bohr orbit of the hydrogen atom is -328 kJ mol^-1; hence the energy of fourth Bohr orbit would be

• -41 kJ mol^-1

• -1312 kJ mol^-1

• -164 kJ mol^-1

• -82 kJ mol^-1

If the energy difference between the ground state of an atom and its excited state is 4.4× 10^-4J, the wavelength of photon required to produce the transition :

• 2.26 × 10^-12m

• 1.13 × 10^-12m

• 4.52× 10^-16m

• 4.52 × 10^-12m

Splitting of spectrum lines in magnetic field is

• Stark effect

• Raman effect

• Zeeman effect

• Rutherford effect

Decrease in atomic number is not observed during

• β- emission

• α- emission

• positron emission

• electron capture

According to Bohr's theory, the angular momentum for an electron in 5^th orbit is

• 2.5 h/ $\mathrm{\pi }$

• 5 h/ $\mathrm{\pi }$

• 25 h/ $\mathrm{\pi }$

• 5 $\mathrm{\pi }$/ 2h

219.

If a species has 16 protons, 18 electrons and 16 neutrons, the symbol (with charge) of species is

• S^-

• Si^2-

• P^3-

• S^2-

'No two electrons in an atom can have the same set of  quantum numbers.' This principle is known by which one of the following?

• Zeeman's exclusion principle

• Stark's exclusion principle

• Pauli's exclusion principle

• Hersbach's exclusion principle