Sch2102:Atomic Structure Question Paper
Sch2102:Atomic Structure
Course:Bachelor Of Science
Institution: Meru University Of Science And Technology question papers
Exam Year:2013
QUESTION ONE (30 MARKS) a) Boron has two naturally occurring isotopes,10B and 11B, which have masses 10.0129 and 11.0093 amu, respectively. Given the average atomic mass of boron (10.81amu), determine the percentage abundance of each isotope. (5 Marks) b) Define the following terms with examples i. Molecules (2 Marks) ii. Compound (2 Marks) c) Discuss four properties of waves. (4 Marks) d) Discuss an experiment whose result can prove that wave nature of light. (4 Marks) e) Red light with a wavelength of 684nm travels through Pyrex glass less slowly than in a vacuum with a frequency of 2.92 × 1014??-1. Calculate the speed of this light. (4 Marks) f) State the following i. The Pauli’s exclusion principle (2 Marks) ii. The Aufbau Principle (2 Marks) iii. Hund’s Rule. (2 Marks) g) Write the electron configuration for the following elements i. 43Tc (1 Mark) ii. 24Cr (1 Mark) iii. 29Cu (1Mark)
QUESTION TWO (20 MARKS)
a) Calculate the energy of
2
i. A proton with a wavelength of 5.00 × 104????. (2 Marks) ii. A proton with a wavelength of 52nm. (2 Marks) iii. Calculate the kinetic energy of an electron ejected by the proton in part (ii) from a metal with a binding energy of 3.7eV. (2 Marks) b) i) State the Rydberg equation. (2 Marks) ii) Calculate the wavelength of the proton emitted when an electron transitions from the n=4 state to the n=2 state in a hydrogen atom. (4 Marks) c) Discuss the de Broglie hypothesis which provided a solution to Bohr’s theory of the line spectrum of hydrogen. (8 Marks)
QUESTION THREE (20 MARKS)
a) i) What is the lowest possible value of the principal quantum number(n) when the angular momentum number(l) is 1? (2 Marks) ii) What are the possible values of the angular momentum quantum number(l) when ml is 0? (2 Marks) b) What are the p and d orbitals? (8 Marks) c) Using quantum numbers, explain why there is no 3f subshell. (4 Marks) d) Write the electron configurations and give the orbital diagram of a bromine (Br) atom (z=35). (4 Marks)
QUESTION FOUR (20 MARKS)
a) Arrange the energies of orbitals in a many-electron atom. (4 Marks) b) The average distance between Mars and Earth is about 1.3 × 108??????????. How long would it take video images transmitted from the mars spirit rover on mars surface to reach Earth (1 mile = 1.61 km)? (5 Marks) c) Consider the following energy levels of a hypothetical atom ??4:-1.0 × 10-19?? ??3:-5.0 × 10-19?? ??2:-10.0 × 10-19?? ??1:-15.0 × 10-19??
i. What is the wavelength of the proton needed to excite an electron from ??1 to ??4. (3 Marks) ii. What is the energy a proton must have to excite an electron from ??2 to ??3? (3 Marks) iii. When an electron drops from the ??3 level to the ??1 level the atom is said to undergo emission. Calculate the wavelength of the proton emitted in this process. (4 Marks) d) Define ground state. (1 Mark)
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