Periodicals generally fall within three categories: scholarly, trade, and popular. While there are some similarities, there are also very distinct differences. The chart and links below provide excellent overviews.
Scholarly vs Trade vs Popular - chart
Evaluating Resources: Scholarly, Trade, and Popular - video
Popular, Scholarly, or Trade? - video
Exploring and Evaluating Trade, Popular, and Scholarly Sources - guide
Research Foundations: Popular, Scholarly, and Trade - guide; includes benefits and drawbacks of each type
You can also verify the type of periodical by checking Ulrichsweb. After typing the title of the periodical, look at content type to see if it is Academic/Scholarly, Trade, or Consumer (popular).