Sch2102:Atomic Structure Question Paper
Sch2102:Atomic Structure
Course:Bachelor Of Science
Institution: Meru University Of Science And Technology question papers
Exam Year:2010
QUESTION ONE (30 MARKS)
a) Define the following terms; i. Wavelength ii. Frequency iii. Orbital iv. Electromagnetic spectrum (4 Marks) b) i) State the Pauli’s exclusion principle. (2 Marks) ii) Write the electronic configuration for the elements wit atomic numbers; 19, 24, 36 and 56. (4 Marks) iii) Indicate the group and period in which each of the elements in b (ii) above belong to. (8 Marks) c) draw the shapes for each of the following orbitals i. 3Pz ii. 3dx2-y2 iii. 4dz2 iv. 4S (6 Marks) d) i) State the Heisenberg’s uncertainty principle. (2 Marks) ii) What is the minimum uncertainty in the position of an electron whose uncertainty in position is 1.3 × 107/. Given: mass of electron = 9.1091 × 1031 Planck’s constant = 6.626 × 1034 (4 Marks)
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QUESTION TWO (20 MARKS)
a) Write the general form of the Schrodinger wave equation and define each of the terms in it. (8 Marks) b) List the conditions that the wave function must satisfy for the meaningful solution of the Schrodinger waver equation. (4 Marks) c) i) State Hund’s rule. (2 Marks) ii) How many unpaired electrons are there in each of the elements with atomic numbers 29, 49 and 54? (6 Marks)
QUESTION THREE (20 MARKS)
a) i) List the four quantum numbers that are necessary to completely describe the behaviour of an electron in an atom. (4 Marks) ii) Briefly describe the significance of each quantum number. (4 Marks) b) Write down all the permissible sets of quantum numbers for the valence electrons in elements of atomic numbers; 8 and 17. (8 Marks) c) What is the maximum number of electrons that can be found in each of the following sub shells? i. 2s ii. 4f iii. 3d iv. 5p (4 Marks)
QUESTION FOUR (20 MARKS)
a) Write balanced ionic equations of the following reactions; i. Zn(s) + CuSO4(aq) ZnSO4(aq) + Cu(s) ii. Ag(s) + HNO3(aq) AgNO3(aq) + NO(g) +H2O(l) iii. Fe2(SO4)3 (aq) +KI(aq) FeSO4(aq) +I2(l) +K2SO4(aq) (6 Marks) b) For an electron to remain in its orbit the centrifugal force and the electrostatic attraction must be equal. Given that the centrifugal force, = 2/ and electrostatic attraction = 2/402. i. Using the angular momentum of the electron = /2 derive an equation for the radius of a Bohr atom. (7 Marks) ii. Calculate the radius of the first Bohr orbit for Li2+ ion. (3 Marks) iii. Calculate the velocity of the electron in Bohr orbit for Li2+ ion. (4 Marks) Given that: = 9.1091 × 1031 Permitivity of vacuum, 0 = 8.854185 × 10121 3 3 Charge of electron, e = 1.6021 × 1019 Planck’s constant, h = 6.626 × 1034
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