A lot of good information, but the text-embedded ads are distracting and could potentially be confusing to high-school students, who may think they are related to the element that they selected. One ad in particular, looked like a quiz that could be interpreted as a site-related activity. I also noticed some grammatical errors in the "History of Carbon" section that I attribute to some sort of "find and replace" programming issue. It said "Carbon was discovered by Known [sic] since ancient times although not recognized [sic] as an element until much later. at no data in not known." I get what it's trying to say, but it doesn’t make grammatical sense the way that it's structured. Again, for high school students, this would be confusing.