[Mikez]

How is reactivity detrimined? my books says it's the closer to 8e- the more reactive but then what about Hydrogen and Argon?

What is the oxidiation number?

[sirius]

If it's got 7 e- (like fluorine), it's very very reactive. If it's got 8 e- (like argon) it's a noble gas so it's not reactive at all. The group 1 metals (alkali) are also very reactive. The ones towards the middle are not as reactive as the ones on the ends of the periodic table (excluding nobles gases, the last group)

[Mikez]

How reactive would elements like Hyrdogen be?

How do I compare the reactivity with those with the same amount of valence e-?

oxidation number? is that it's charge, for example O -2?

[Albert]

oxidation number? is that it's charge, for example O -2?

Not at all, or at least, not always (i.e. O has -1 and -2 as oxidation numbers).

These numbers are strongly linked to the compound where the element is present and can be assigned only considering a specific oxidation (or reduction) reaction. Only in this particular context, oxidation numbers can be predicted using nearly 6 rules you can easily find in every decent chem book.

How is reactivity detrimined?

Check this out:

http://www.sciencebyjones.com/chemical_reactivity.htm

[Mikez]

thanks the web page helped alot