Many scientists attempted to explain the structure of the atom using atomic models in the 18th and 19th centuries. Each of these models had advantages and disadvantages, which were crucial in developing the modern atomic model. Scientists such as John Dalton, J.J. Thomson, Ernest Rutherford, and Niels Bohr made significant contributions to the field.
In 1915, Neils Bohr proposed his model of the atom. This is the most widely used atomic model for describing an element’s atomic structure, and it is based on Planck’s theory of quantisation.
According to Heisenberg, no two conjugate physical quantities can be measured with 100% accuracy at the same time. There will always be some degree of error or uncertainty in the measurement.
Download PDF of Class 11 Chemistry Chapter 2 Structure of Atom – Set 2
CBSE Class 11 Chemistry Worksheet Chapter 2 Structure of Atom – Set 2
Q1. The ratio of radii of the first three Bohr orbits of H–atom is:
a.) 1 : 2 : 3
b.) 1 : 4 : 9
c.) 1: 3 : 27
d.) 2: 1 : 3
Q2. The azimuthal quantum number for the last electron in the Na atom is:
a.) 1
b.) 0
c.) 2
d.) 3
Q3. How many spherical nodes are present in the 4s orbital in a hydrogen atom?
a.) 0
b.) 2
c.) 3
d.) 4
Q4. If travelling at the same speeds, which of the following matter waves have the shortest wavelength?
a.) Electron
b.) Alpha particle (He2+)
c.) Neutron
d.) Proton
Q5. The spectral line in the hydrogen spectrum obtained when the electron jumps from n = 5 to n = 2 energy level belongs to:
a.) Lyman series
b.) Balmer series
c.) Paschen series
d.) Pfund series
Q6. What will be the wavelength associated with a moving particle if its velocity is doubled?
Q7. Differentiate between emission and absorption spectra.
Q8. The wavelength of blue light is 480 nm. Calculate the frequency and wave number of this light.
Q9. Which of the following sets of orbitals are degenerate and why?
i.) 1s, 2s and 3s in Mg atom.
ii.) 2px, 2py and 2pz in C atom
iii.) 3s, 3px and 3d orbitals in H atom.
Q10. Complete the following table:
|
Particle |
Mass Number |
Atomic Number |
Protons |
Neutrons |
Electrons |
|
O |
8 |
8 |
|||
|
Al |
27 |
13 |
|||
|
Cl– |
35 |
17 |
|||
|
Mg2+ |
12 |
10 |
Q11. An atom has 2 electrons in the first (K) shell, 8 electrons in the second (L) shell and 2 electrons in the third (M) shell. Give its electronic configuration and find out the following:
a.) Atomic number
b.) Total number of principal quantum numbers
c.) Total number of sublevels
d.) Total number of s–orbitals
e.) Total number of p–electrons.
Q12. An electron has a speed of 500 m/s with an uncertainty of 0.02%. What is the uncertainty in locating its position?
Q13. When the light of 470 nm falls on the surface of potassium metal, electrons are emitted with a velocity of 6.4 × 104 m/s. What is the minimum energy required per mole to remove an electron from potassium metal?
Q14. State the features of Planck’s quantum theory.
Q15. How did the wave mechanical model of an atom overrule the circular orbits proposed by Bohr?
Q16. Derive de Broglie’s relationship. What is its significance?
Q17. a.) Give the essential postulates of Bohr’s model of an atom. How did it explain
i.) the stability of an atom?
ii.) origin of spectral lines in a hydrogen atom?
Q18. Calculate the kinetic energy of a moving electron which has a wavelength of 4.8 pm.
(Mass of electron = 9.11 × 10–31 kg, h = 6.63 × 10–34 J s)
Q19. What is the wavelength of light emitted when the electron in a hydrogen atom undergoes a transition from the energy level with n = 4 to the energy level with n = 1? In which region of the electromagnetic spectrum does this radiation fall?
Q20. a.) What is the radial probability distribution curve? Draw radial probability distribution curves for 1s and 2s orbitals.
b.) Discuss the similarities and differences between 1s and 2s orbitals.
c.) How many nodes are present in 1s and 2s orbitals?
Download PDF to access answers of the Chemistry Worksheet for Class 11 Chemistry Chapter 2 Structure of Atom Set – 2.
Read Also:
- Class 11 Chemistry Chapter 2 Structure of Atom MCQs
- Important Questions for Class 11 Chemistry Chapter 2 Structure of Atom
- Chemistry Concept Questions and Answers
- CBSE Class 11 Chemistry Practical
- Aufbau Principle
- Subatomic Particles
- Rutherford Atomic Model
- Planck’s Quantum Theory: Quantisation of Energy
- Bohr’s Model of An Atom
