Generate me an image of a clean educational poster on a pure white background. At the top, large bold text reads "Fluorine". Centered below is a simple minimalist atomic diagram or circular icon. Under the image, neatly stacked text lines read: "neutrons = 9", "electrons = 9", and "protons = 19". Use a modern sans-serif font, black text, lots of white space, and a simple, uncluttered layout. Ver mais