So, I basically have a few questions that I could use some help with.

1) How exactally does one find the coordination number and oxidation number of a metal? For example, [PtCl4(en)]? My book doesn't say much on

*how*to find the coordination number.

2)And, I have a question pertaining to radiation and a lab-rat. Suppose a rat is

**grams, and is exposed to radiation for**

*X***seconds, absorbing 65% of emitted alpha particles, each having energy of 9.2 x 10 to the -13 Joules. What is the absorbed dose in millirads and grays.**

*X***(X in the above question is arbitrary. I don't want the answer to my homework, only how to find the answer, ergo, the X's.)**

3)Where can I go to find out

*how*to draw geometric isomers? My book is vaque. And how and one formula have two different geometric isomers?

4)Half-life? The half-life for the process of Uranium-238 to Lead-206 is 4.5 x 10 to the 9. A mineral sample contains 75 mg of Uranium-238 and 21 mg of Lead-206. What is the age of the mineral? I found an example that would work if I knew the original amount of each element, not what's left.

That's it. Any clarification that anyone can give me will be whole heartedly appreciated. Virtual cookies will flow freely, and lots of XXXXX's. Thanks.

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