This is a tremendously useful website for any grade! I looked at just about every element on the site and found out many different facts that I never learned while I was in school. There was a significant amount of interesting and seemingly useful information for each element that I clicked on.
The site is very easy to use and could wind up being quite addicting to students who use it to their advantage for research, projects, etc.
Time spent reviewing site:
I spent well over an hour tooling around on this site reading and learning about elements I thought I already knew enough about, re-familiarizing myself with others and even learning about the elements I never really knew existed.