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

Which of the following sets of qunatum numbers correct?

• n =5, l=4, m=0, s=+1/2

• n= 3, l=3, m=+3, s= +1/2

• n=6, l=0, m=+1, s= =1/2

• n=4, l= 2, m=+2, s=0

An electron from one Bohr stationary orbit can go to next higher orbit

• by emission of electromagnetic radiation

• by absorption of any electromagnetic radiation

• by absorption of electromagnetic radiation of particular frequency

• without emission or absorption of electromagnetic radiation

Splitting of spectrum lines in magnetic field is

• Stark effect

• Raman effect

• Zeeman effect

• Rutherford effect

236.

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

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

Consider the ground state of Cr atom (Z= 24). The numbers of electrons with the azimuthal quantum numbers, l = 1 and 2 are respectively

• 12 and 4

• 12 and 5

• 16 and 4

• 16 and 5