Great chart printed with different perspectives front and back (“hard” data & descriptions one side, “softer” every day descriptions on other side). Bought two of these for the kids (and me) to help learn the Periodic Table song, which was when we quickly found 7 elements were described as “Unknown”, even though most of them had formalized names by 2010-ish. The last one (Tennessine I think) was formally named in 2016.