A standard CV should be two sides.
If you’re printing your CV, each side should be on its own piece of paper. Then, employers can put the pages side by side or flick through them to easily learn about you. Make it easy for them do this by using a paper clip to attach the two pages.
Printing both sides of your CV onto one page will make employers have to flip the page back and forth to refer to it, which they’ll find inconvenient.
When you’re just sending your CV online (for example, as a PDF), make sure there are no blank pages in the middle. Otherwise, recruiting managers will think they’ve finished reading your CV before they reach the end.