1. Another resource provided by WebElements is a VSEPR tutorial. Examine the example molecules given at http://www.shef.ac.uk/~chem/vsepr.
Study the image of BF3.
(a) Which is the central atom?
(b) How many bonds surround this atom?
(c) Draw a lewis structure.
(d) Are there any lone pairs on the central atom?
(e) Calculate the formal charge on the boron atom.
(f) Calculate the formal charges on the fluorine atoms.
(g) Does this molecule obey the octet rule?
Now, study the methane molecule.
(h) Is a C-H bond polar?
(i) Is methane a polar molecule? If not, why?
Finally, take a look at ammonia.
(j) Draw the lewis structure for ammonia.
(k) Calculate the formal charge on the nitrogen.
(l) Does ammonia have a dipole moment? What makes this molecule different from methane?
2. Chemistry Central provides assistance on basic atomic information, periodic elements, and chemical bonding. After reading the material provided on the page http://library.advanced.org/3659/structures/, answer the questions below.
(a) Why are metals associated with good electrical conductivity?
(b) Why do metals generally lose electrons and nonmetals usually gain electrons?
(c) What makes a bond ionic rather than covalent? How do you differentiate between them?