Atoms

The spectral series which corresponds to the electronic transition from the levels n2 = 5, 6, to the level n1 = 4 is

1. Pfund series
2. Brackett series
3. Lyman series
4. Balmer series

Some energy levels of a molecule are shown in the figure with their wavelengths of transitions. Then : [figure]

1. 3 > 2, 1 = 2 2
2. 3 > 2, 1 = 4 2
3. 1 > 2, 2 = 2 3
4. 2 > 1, 2 = 2 3

In hydrogen spectrum, the shortest wavelength in the Balmer series is . The shortest wavelength in the Brackett series is :

1. 4
2. 9
3. 16
4. 2

The radius of inner most orbit of hydrogen atom is 5.3 10-11 m. What is the radius of third allowed orbit of hydrogen atom?

1. 1.06 Å
2. 1.59 Å
3. 4.77 Å
4. 0.53 Å

Let T1 and T2 be the energy of an electron in the first and second excited states of hydrogen atoms, respectively. According to the Bohr's model of an atom, the ratio T1 : T2 is

1. 1 : 4
2. 4 : 1
3. 4 : 9
4. 9 : 4

Let R1 be the radius of the second stationary orbit and R2 be the radius of the fourth stationary orbit of an electron in Bohr's model. The ratio R1R2 is :

1. 4
2. 0.25
3. 0.5
4. 2

For which one of the following, Bohr model is not valid?

1. Singly ionised helium atom (He+)
2. Deuteron atom
3. Singly ionised neon atom (Ne+)
4. Hydrogen atom

-particle consists of :

1. 2 electrons, 2 protons and 2 neutrons
2. 2 electrons and 4 protons only
3. 2 protons only
4. 2 protons and 2 neutrons only

The total energy of an electron in an atom in an orbit is -3.4 eV. Its kinetic and potential energies are, respectively.

1. 3.4 eV, -6.8 eV
2. 3.4 eV, 3.4 eV
3. -3.4 eV, -3.4 eV
4. -3.4 eV, -6.8 eV

The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom, is

1. 1 : 1
2. 1 : -1
3. 2 : -1
4. 1 : -2