You should go to your AdSense account and find the AdSense Terms and the AdSense Localized Terms. Read them carefully.
There is a limit to the number of AdSense ads of various types that you can place on a page. My understanding is that the limit is currently 3 AdSense ads per web page.
So if each of your blog articles is on its own page, it would be ok to put an ad unit (or perhaps even 3) on the page, but if you have more than one article per page, then you should not put an ad in each one because then you might end up with more than 3 ads on a page and would be breaking the rules.