Thursday 11:17

This felt extremely fast, and I thought it might be a PB, but there was an 8:59 back in July 2018. There were a number of 2-letter answers, each being an element matching with the atomic number of the numbered square. I could have searched up a periodic table to get all those right away, but it might have taken even more time to find a readable table and correspond the numbers. I don't know the elements Nd and Sm (Neodynium and Samarium? Ooookay), but the others were familiar enough. Nice design, too, with two 15-letter downs crossing two 13-letter acrosses.