Finished the first chapter, and I take what I said back. Sam Kean isn't condescending; he's trying to imitate his earlier terrible teachers and mystify us.
I thought I understood the periodic table, but Kean's explanations were all over the place and diverged into so many tangents about Plato and various early chemists and atomic physicists that I'm not sure that he actually explained anything. He threw around some facts but that's about it.
The endnotes, such as they are, are useless since they don't appear to contain any actual references, just stuff that Kean decided he didn't want in the main text. And he throws around references to temperatures in degrees Fahrenheit, an entirely useless unit. If Kean isn't going to try to appeal to an international audience by including sensible units, I don't see why an international audience should bother to read him. I think I'm throwing in the towel. I don't see the point of this book.
page 11 of 346 (update after introduction)