# Structure Of Atom Important Questions

Given below are the Structure Of Atom Class 11 Important Questions
a. Concepts questions
b. Calculation problems
d. Quantum number and EC problems

Question 1.
Why are the half filled and Fully Orbitals more stable?

Question 2.
Describe the Rutherford's Model of the atom and decribe the drawback of it

Question 3.
Give the electronic configuration of the following ions
(i) H-
(ii) N3-
(iii)O2-
(iv) Li+
(v)Na+
((vi)F-

Question 4.
What are the drawbacks of Bohr's Theory

Question 5.
What are degenerate orbitals.Explain with examples

Question 6.
Differentiate betweem an orbit and orbital

Question 7.
Using s,p,d notations, describe the orbital with the following quantum?
(i) n=2, l=1
(ii) n=4, l=1
(iii) n=4, l=2
(iv) n=3, l=1
(v) n=2 ,l=0
(vi) n=4, l=3

Question 8.
State de-broglie relation

Question 9.
What is Ridberg's constant?. What its numerical value

Question 10.
What is Probability Density

Question 11.
State and explain Pauli's exclusion principle

Question 12.
State and explain Heisenberg's uncertainty principle.

Question 13.
Arange the orbitals represented by the following sets of energy
(i)n=4,l=0,ml=0, ms= +1/2
(ii)n=3,l=2,ml=0, ms= -1/2
(iii)n=3,l=1,ml=0, ms= +1/2
(iv)n=3,l=0,ml=0, ms= -1/2

Question 14.
An electron is one of the 3d orbitals. What are the possible values of n,l,ml for this electron

Question 15.
State the number of protons, neutrons and electrons in
(i) 12C6
(ii) 14C6

## Numericals Problems

Question 1.
Calculate the Kinetic energy of a moving electron which has a wavelength of 4.9 pm.
Mass of Electron=9.11 × 10-31 kg
Plank's Constant (h)=6.63 × 10-34 J-s

Question 2.
Calculate the wavelength and energy of the radiation emitted for the electronic transition from fourth orbit to stationary state 1 of He+ ion.
RH=1 × 107 m-1
Plank's Constant (h)=6.63 × 10-34 J-s

Question 3.
what will be the wavelength of a ball of mass .1 kg moving with velocity 10 m/s?

Question 4.
Calculate the wave number for the longest wavelength transition in the balmer series of atomic hydrogen ( Ans $1.525 \times 10^6 m^{-1}$)

Question 5.
An electron is moving with the kinetic energy of 2.275 × 10-25 J. Calculate its De-Broglie wavelength?
Mass of Electron=9.11 × 10-31 kg
Plank's Constant (h)=6.63 × 10-34 J-s

Question 6.
A photon ($\lambda = 4 \times 10^{-7} \ m$) strikes a metal surface of Work function(W=2.13 eV).Calculate
(i) Energy of Photon in eV
(ii) K.E of the emission
(iii)Velocity of the photoelectron
1 eV=1.6020 × 10-19 J
Plank's Constant (h)=6.63 × 10-34 J-s
Mass of Electron=9.11 × 10-31 kg

Question 7.
Calculate the uncertainty in the momentum of an electron if it is confined to a linear region of length $1 \times 10^{-10}$ metre.

Question 8.
Calculate
(i)first excitation energy of the electron in the hydrogen atom
(ii) Ionization energy of the hydrogen atom

Question 9.
Calculate the velocity of an electron placed in the third orbit of the hydrogen atom.Also Calculate the number of revolution per second that this electron makes around the nucleus?

Question 10.
Electromagnetic radiation of wavelength 242 nm is just sufficient to ionize the sodium atom. Calculate the ionisation energy of Sodium in KJ/mol

Question 11.
Determine the number of unpaired electrons in the ground state of below ions
(i) Ar+
(ii)Sn2+
(iii) F+
(iv)Bi3+

Question 12.
The arrangement of orbitals on the basis of energy is based upon their (n+l ) value. Lower the value of (n+l ), lower is the energy. For orbitals having same values of (n+l), the orbital with lower value of n will have lower energy.
I. Based upon the above information, arrange the following orbitals in the increasing order of energy.
(a) 1s, 2s, 3s, 2p
(b) 4s, 3s, 3p, 4d
(c) 5p, 4d, 5d, 4f, 6s
(d) 5f, 6d, 7s, 7p
II. Based upon the above information, solve the questions given below :
(a) Which of the following orbitals has the lowest energy?
4d, 4f, 5s, 5p
(b) Which of the following orbitals has the highest energy?
5p, 5d, 5f, 6s, 6p