Structure of Atom quiz

The charge on an electron was determined by:

The neutron was discovered by:

Which quantum number determines the shape of an orbital?

The maximum number of electrons in a shell with n = 3 is:

The Balmer series of hydrogen lies in the:

The electronic configuration of Cr is:

The number of radial nodes in a 3s orbital is:

Isotopes have the same:

Which set of quantum numbers is not allowed?

The radius of the first Bohr orbit of hydrogen is:

What did Thomson's experiment with cathode rays show? (2 marks)

What are the main features of Thomson's model of the atom? (2 marks)

What is meant by the dual nature of matter? (2 marks)

Why is Bohr's model not applicable to multi-electron atoms? (2 marks)

What is an orbital? How does it differ from an orbit? (2 marks)

What is the (n + l) rule? (2 marks)

Write the electronic configuration of Fe and Fe3+ (Z = 26). (2 marks)

Why are half-filled and completely filled orbitals more stable? (2 marks)

What is a nodal plane? How many does a p orbital have? (2 marks)

What is meant by degenerate orbitals? (2 marks)

Calculate the radius of the third Bohr orbit of hydrogen (r1 = 52.9 pm). (3 marks)

Calculate the energy required to ionise a hydrogen atom in its ground state. (3 marks)

How many orbitals and electrons can be present in the shell with n = 4? (3 marks)

Calculate the number of protons, neutrons and electrons in 35Cl and 37Cl (Z = 17). (3 marks)

Calculate the wavenumber of the first line of the Balmer series (n = 3 to 2), using wavenumber = 109,677 (1/n1^2 - 1/n2^2) per cm. (3 marks)

Read the passage and answer the questions. Rutherford bombarded a very thin gold foil with alpha particles. Most of the alpha particles passed through the foil undeflected. A small fraction was deflected by small angles, and a very few (about 1 in 20,000) bounced back. (i) What did most particles passing through indicate? (ii) What did the few rebounding particles indicate? (iii) What was the main drawback of his model? (5 marks)

Read the passage and answer the questions. When light of a suitable frequency strikes the surface of certain metals such as potassium, rubidium and caesium, electrons are ejected. The number of electrons depends on the intensity of light, but the kinetic energy depends on its frequency. No electrons are emitted below a certain frequency, however intense the light. (i) What is the threshold frequency? (ii) Write Einstein's photoelectric equation. (iii) Why could the wave theory not explain this effect? (5 marks)

Read the passage and answer the questions. Electrons in a hydrogen atom can occupy only certain energy levels. When an electron jumps from a higher to a lower level, it emits a photon whose energy equals the difference between the levels. This gives the line spectrum of hydrogen. (i) Why is the hydrogen spectrum a line spectrum? (ii) Which series lies in the ultraviolet region? (iii) Calculate the energy of the electron in the n = 2 level. (5 marks)

Read the passage and answer the questions. De Broglie proposed that matter, like radiation, should also exhibit dual behaviour, that is both particle and wave-like properties. This means that just as the photon has momentum as well as wavelength, electrons should also have momentum and wavelength. The prediction was confirmed by the diffraction of electrons. (i) Write the de Broglie equation. (ii) Name one instrument that uses the wave nature of electrons. (iii) Why is the de Broglie wavelength of a moving car negligible? (5 marks)

Read the passage and answer the questions. The filling of electrons into the orbitals of different atoms takes place according to the Aufbau principle, the Pauli exclusion principle and Hund's rule of maximum multiplicity. For nitrogen (Z = 7), the configuration is 1s2 2s2 2p3, with the three 2p electrons in separate orbitals with parallel spins. (i) Which rule explains the arrangement of the 2p electrons? (ii) Write the configuration of oxygen (Z = 8). (iii) How many unpaired electrons does oxygen have? (5 marks)

Describe the discovery of the electron, proton and neutron. Explain the charge to mass ratio of the electron and Millikan's experiment. (6 marks)

Explain Thomson's and Rutherford's models of the atom with diagrams. What were their limitations? (6 marks)

Explain the wave nature of electromagnetic radiation, Planck's quantum theory and the photoelectric effect. (6 marks)

Explain Bohr's model of the hydrogen atom. Derive the energy of the electron in the nth orbit and explain the hydrogen spectrum. (6 marks)

Explain the quantum mechanical model of the atom. Describe quantum numbers, the shapes of orbitals and the rules for filling electrons. (6 marks)