You can view journal impact factors by using the Scopus database. Scopus calls this "CiteScore" as opposed to impact factors. Below you will see how to quickly and easily access this information.
Once in Scopus, click on the "sources" link at the top of the page.
Here you are able to see the CiteScore filter.
You are able to search within these results, as well as use the filters on the left to narrow your results. One useful filter is the top 10% filter. This allows you to view journals with the highest impact factor with one click.