Chemistry

Structure of Atom

Question:

The Balmer series in the hydrogen spectrum corresponds to the transition from n1 = 2 to n2 = 3, 4,……… This series lies in the visible region. Calculate  the wave number of line associated with the transition in Balmer series when the electron moves to n = 4 orbit. (RH = 109677 cm-1).

Answer:

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Structure of Atom

Q 1.

Which series of lines of the hydrogen spectrum lie in the visible region?

Q 2.

The electronic configuration of valence shell of Cu is 3d10 4s 1 and not 3d94s2. How is this configuration explained?

Q 4.

Giue flic name and atomic number of the inert gas atom in which the total number of d-electrons is equal to the difference between the numbers of total p and total s-electrons.

Q 5.

An anion A3+has 18 electrons. Write the atomic number of A.

Q 6.

Write the electronic configuration and number of unpaired electrons in  Fe2+ion.

Q 7.

What is the minimum product of uncertainty in position and momentum of an electron?

Q 8.

What is the most important application of de Broglie concept?

Q 9.

How many electrons in an atom can have n + l = 6?

Q 10.

Which of the following will not show deflection from the path on passing through an electric field?
Proton, cathode rays, electron, neutron.

Q 11.

Define atomic number, mass number and neutron. How are the three related to each other?

Q 12.

If n is equal to 3, what are the values of quantum numbers l and m?

Q 13.

Which one  Fe3+, Fe2+is more paramagnetic and why?

Q 14.

Discuss the similarities and differences between a 1s and a 2s orbital.

Q 15.

When is the energy of electron regarded as zero?

Q 16.

Show the distribution of electrons in oxygen atom (atomic number 8) using orbital diagram.

Q 17.

What mil be the order of energy levels 3s, 3p and 3d in case of H-atom?

Q 18.

Give the relation between wavelength and momentum of moving microscopic particle. What is the relation known as?

Q 19.

Which element does not have any neutron?

Q 20.

Distinguish between a photon and quantum.

Q 21.

Arrange the electron (e), protons (p) and alpha particle (α) in the increasing order for the values of e/m (charge/mass).

Q 22.

The Balmer series in the hydrogen spectrum corresponds to the transition from n1 = 2 to n2 = 3, 4,……… This series lies in the visible region. Calculate  the wave number of line associated with the transition in Balmer series when the electron moves to n = 4 orbit. (RH = 109677 cm-1).

Q 23.

What were the weaknesses or limitations of Bohr’s model of atoms ? Briefly describe the quantum mechanical model of atom.

Q 24.

An atom having atomic mass number 13 has 7 neutrons. What is the atomic number of the atom?

Q 25.

The uncertainty in the position of a moving bullet of mass 10 g is  10-5    m. Calculate the uncertainty in its velocity?

Q 26.

What is value of Planck’s constant in S.I. units?

Q 27.

Which orbital is non-directional?

Q 28.

Show the distribution of electrons in oxygen atom (atomic number 8) using orbital diagram.

Q 29.

What is the difference between ground state and excited state?

Q 30.

Arrange X-rays, cosmic rays and radio waves according to frequency.

Q 31.

What are degenerate orbitals ?

Q 32.

What type of metals are used in photoelectric cells? Give one example.

Q 33.

The uncertainty in the position and velocity of a particle are  10-10m and  5.27 x 10-24 ms-1  respectively. Calculate the mass of the particle. (Haryana Board 2000)

Q 34.

What is common between dxy  and  dx2-y 2  orbitals?

Q 35.

Using Aufbau principle, write the ground state electronic configuration of following atoms.
(i)Boron (Z = 5) (ii) Neon (Z = 10), (iii) Aluminium (Z = 13) (iv) Chlorine (Z = 17), (v) Calcium (Z = 20) (vi) Rubidium (Z = 37)

Q 36.

Arrange s, p and d sub-shells of a shell in the increasing order of effective nuclear charge (Zeff) experienced by the electron present in them

Q 37.

What is the difference between the notations l and L?

Q 38.

State and explain the following:
(i) Aufbau principle
(ii) Pauli exclusion principle.
(iii) Hund’s rule of maximum multiplicity.

Q 39.

An electron beam after hitting a neutral crystal produces a diffraction pattern? What do you conclude?

Q 40.

The kinetic energy of an electron is  4.55 x 10-25 J. The mass of electron  9.1 x 10-1 kg.  Calculate velocity, momentum and the wavelength of the electron?(Haryana Board, 2004, AII CBSE 2000)

Q 41.

Calculate the total number of angular nodes and radial nodes present in 3p orbital.

Q 42.

What are the two longest wavelength lines (in manometers) in the Lyman series of hydrogen spectrum?

Q 43.

In a hydrogen atom, the energy of an electron in first Bohr’s orbit is  13.12 x 105 J mol-1.  What is the energy required for its excitation to Bohr’s second orbit?

Q 44.

What is difference between the notations l and L?

Q 45.

(a) What is the limitations of Rutherford model of atoms?
(b) How has Bohr’s theory helped in calculating the energy of hydrogen electron in different energy levels?

Q 46.

An electron beam on hitting a ZnS screen produces a scientillation on it. What do you conclude?

Q 47.

Calculate the de Broglie wavelength of an electron moving with 1% of the speed of light?

Q 48.

How many unpaired electrons are present in Pd (Z = 46) ?

Q 49.

With what velocity must an electron travel so that its momentum is equal to that of a photon of wavelength = 5200 A?

Q 50.

Which of the following orbitals are degenerate?
3dxy, 4dxv, 3dyz, 3dz2:, 4dyz., 4dz2: