How many known elements could we delete without ill effect? Part 2

Ted Streshinsky/CORBIS/Corbis via Getty Images How many of the 118 known elements in the periodic table could we permanently delete without any ill effect on our lives? (continued) Guy Cox Sydney, Australia Previous correspondent Mike Follows is far too stingy in his list of elements essential for life. The mnemonic CHOPKINS CaFe, mighty good – carbon (C), hydrogen (H), oxygen (O), phosphorus (P), potassium (K), iodine (I), nitrogen (N), sulphur (S), calcium (Ca), iron (Fe) and magnesium (Mg) – teaches us the essential elements for plant growth, to which we also have to add sodium and chloride (no salt on the table in this cafe?). Magnesium, by the way, is required for chlorophyll, which enables photosynthesis to take place. But there are essential trace elements we humans also need in sma