On Tuesday morning I shared a collection of seven good resources to help students learn the Periodic Table of Elements. The next day Open Culture shared this periodic table visualization that shows the country and year in which each element was discovered.
(If you cannot see the image it is because your network is blocking imgur which hosts the image).
The visualization is based on this Wikipedia hosted Timeline of Chemical Element Discoveries. You want to double-check the accuracy or have students look for points of contention surrounding some of the claims.