sampleqnsfromoldtests.O01

sampleqnsfromoldtests.O01 - 1 ATOMIC STRUCTURE RADIUS...

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1. ATOMIC STRUCTURE, RADIUS, BONDING AND COORDINATION (1) Answer True or False 1. The electrons are heavier than the neutrons. 2. Covalent bond is formed when the electrons resonate in the orbitals between the bonded atoms. 3. Ionic bonding prevails in ceramic materials. (T) 4. A negative ion has larger volume than the positive ion of the same atom. (T) 5. Free electrons are responsible for electrical conduction. 6. The number of single bonds a carbon atom can form is 4. 7. The inter-atomic distance is always 2r, where r is the radius of atoms. (F) 8. The coordination polyhedron referred to as tetrahedron is found in diamond. (T) 9. In body centered cubic structure of iron the atom at the body center is touching the corner atoms. (T) 10. Covalent bond is when electrons between bonded atoms are shared with each other. 11. Van der Waals bond is stronger than the ionic bond. 12. In covalent bonds more the number of electrons in bonds shorter will be the inter-atomic bond lengths. 13. In ionic bonding free electrons prevalent are utilized in bonding adjacent atoms. 14. The positive ions are smaller in size than the neutral atom of the same kind. (T) 15. The inter-atomic distance is always 2r, where r is the radius of atoms. (F) 16. The atomic weight of carbon is 12. The mass of a carbon atom would be roughly 2 microgram. (F) 17. The atomic number of an element indicates the number of electrons in a normal neutral atom of that element. (T) 18. The atomic weight is used to find the mass of an ion. (2) Fill in the blanks 1. A sodium atom, when it loses an electron, becomes ______and ________. 2. An example for a covalently bonded material is: ________. 3. The atomic number of iron is 26. The ferrous Fe 2+ ion has ___electrons and ______ protons. 4. Atomic number of Phosphorous is 15. The number of free electrons in a P- atom is ______. 5. Write down the bond structure of vinyl chloride, C 2 H 3 Cl. ________. 6. A copper atom, when it loses two electrons, becomes _____ and _____. 7. An anion is produced when _____________. 8. An example for ionic bonding is found in ______. Here the positive ____ion is bonded to negative ________ion through electrostatic forces of attraction. 1
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3) Answer questions 9. Define covalent bond. 10. What are two differences between Fe and Fe 2+ ? 2. CRYSTAL STRUCTURE IN MATERIALS (1) Answer True or False 1. The plane (002) does not cut the y-axis. (T) 2. The direction [111] passes through the origin. (T) 3. There are four atoms per unit cell in bcc crystals. (F) 4. As the lattice parameter of the cubic unit cell increases, the radius of the atom in it will increase. 5. The atomic number of an element gives the mass of an atom of that element. (F) 6. BCC crystals have densely packed planes as found in FCC and HCP crystals. (F) 7. Atoms are more densely packed if the packing factor is high. (T) 8. Planes (240) make intercept of ½, ¼, and 0 with x, y and z axes. (F) 9. Lead and nickel both have f.c.c structures. The lattice parameter of
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This note was uploaded on 01/22/2012 for the course ME 2733 taught by Professor Meng during the Fall '10 term at LSU.

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sampleqnsfromoldtests.O01 - 1 ATOMIC STRUCTURE RADIUS...

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