The  energy needed to convert helium atom  to He ⁺² is -79eV. The first ionization energy of this atom is about 

1. 65.4eV

2. 51.8eV

3. 24.6eV

4. 27.2eV

Elements upto atomic number 103 have been synthesized and studied. If a newly discovered element is found to have an atomic number 106, its electronic configuration will be -

1. [Rn] 5f¹⁴, 6d⁴, 7s²

2. [Rn] 5f¹⁴, 6d¹, 7s² 7p³

3. [Rn] 5f¹⁴, 6d, 7s⁰

4. [Rn] 5f¹⁴, 6d⁵, 7s¹

The most probable radius (in pm) for finding the electron in He⁺ is -

1. 0

2. 52.9

3. 26.5

4. 105.8

The mass ratio of photons corresponding to the first lines of the Lymann and the Balmer series of the atomic spectrum of hydrogen is :

An electron, practically at rest, is initially accelerated through a potential difference of 100 volts. It then has a de Broglie wavelength=$\lambda$₁Å. It then get retarded through 19 volts and then it has wavelength $\lambda$₂ Å. A further retardation through 32 volts changes the wavelength to $\lambda$₃.

What is ($\lambda$₃-$\lambda$₂)/$\lambda$₁?

1. 20/41

2. 10/63

3. 20/63

4. 10/41

Which of the following has the maximum number of  unpaired electons-

1. Mg²⁺

2. Ti³⁺

3. V³⁺

4. Fe²⁺

There are three energy levels in an atom. How many spectral lines are possible in its emission spectra?

1. One

2. Two

3. Three

4. Four

Azimuthal quantum number defines -

1. e/m ratio of electron

2. Spin of electron

3. Angular momentum of electron

4. Magnetic momentum of electron

For the energy levels in an atom, which one of the following statements is correct -

1. There are seven principal electron energy levels

2. The second principal energy level can have two 'sub energy levels and contains a maximum of eight electrons

3. The energy level can have a maximum of 32 electrons

4. The 4s sub-energy level is at higher energy than the 3d sub-energy level

Arrange the following particles in increasing order of values of e/m ratio: Electron(e), proton(p), neutron(n) and α-particle(α)

1. n,p,e,α

2. n,α,p,e

3. n,p,α,e

4. e,p,n,α