Re: What's the link b/t how active a metal is and where it is on the per. table

There really isnt any direct correlation between what elements you can't 
use in a school lab and their placement on the periodic table. With 
elements like potassium that are dangerous, there is a little correlation; 
that's because position is based on properties, so elements with similar 
properties are also going to be dangerous. 

All of the group one elements are dangerous. Lithium, sodium, etc., all react 
violently with water. Also, at least in a high school lab, you probably will 
not see many gases. Gases have to be stored in tanks or similar things so they 
are under pressure -- that is a hazard in itself -- and most of them are 
poisonous, like chlorine. 

Expensive elements like gold, on the other hand, are available. It is just 
that most high school labs do not have the budget to spend on such things. 
What makes them expensive is usually how rare they are. There really is 
not much correlation between these elements and their placement on the 
periodic table. 

I would like to point out that dangerous elements can be found 
in the lab. Usually they are immersed in mineral oil, or in safe compounds. 

I hope this answers your question.