I need some help with my current chemistry lesson. I have trouble understanding the basics of nuclear chemistry. Alpha, Beta, gamma, Half-Life, and so on.  

Some Questions I have are: 

How to write a nuclear equation for beta decay? (Strontium-90)

How do I solve Half-Life Problems? (For examples How old is an artifact if four half-lives have occurred and the half-life of carbon-14 us 5730 years? Another Question is The half-life of Cobalt-60 is 5.26 years. How many half-lives have passed in 10.52 years?)