Week 6 – Periodic Table of Elements 1. There’s antimony, arsenic, aluminum, selenium, And hydrogen and oxygen and nitrogen and rhenium And nickel, neodymium, neptunium, germanium, And iron, americium, ruthenium, uranium, Europium, zirconium, lutetium, vanadium And lanthanum and osmium and astatine and radium And gold, protactinium and indium and gallium And iodine and thorium and thulium and thallium. There’s yttrium, ytterbium, actinium, rubidium And boron, gadolinium, niobium, iridium And strontium and silicon and silver and samarium, And bismuth, bromine, lithium, beryllium and barium. There’s holmium and helium and hafnium and erbium And phosphorous and francium and fluorine and terbium And manganese and mercury, molybdinum, magnesium, Dysprosium and scandium and cerium and cesium And lead, praseodymium, and platinum, plutonium, Palladium, promethium, potassium, polonium, Tantalum, technetium, titanium, tellurium, And cadmium and calcium and chromium and curium. There’s sulfur, californium and fermium, berkelium And also mendelevium, einsteinium and nobelium And argon, krypton, neon, radon, xenon, zinc and rhodium And chlorine, carbon, cobalt, copper, Tungsten, tin and sodium. These are the only ones of which the news has come to Harvard, And there may be many others but they haven’t been discovered. 7. THE ARICLE: ARSENIC Arsenic is the chemical element that has the symbol As, atomic number 33 and 1 atomic mass 74.92. Arsenic was first documented by Albertus Magnus in 1250. The element is a steel grey, very brittle, crystalline solid. Arsenic is a poisonous element that occurs in the earth’s crust. It is metalloid with 2 many allotropic forms, including a yellow (molecular non-metallic) and several black and grey forms (metalloids). Three metalloidal forms of arsenic, each with a different crystal structure, are found free in nature. The most stable of arsenic's isomers is 68mAs with a half-life of 111. In the environment, arsenic is combined with oxygen, chlorine, and sulfur to form 3 inorganic arsenic compounds. Arsenic in animals and plants combines with carbon and hydrogen to form organic arsenic compounds. The most common oxidation states for arsenic are −3 (arsenides: usually alloy-like intermetallic compounds), +3 (arsenates(III) or arsenites, and most organoarsenic compounds), and +5 (arsenates: the most stable inorganic arsenic oxycompounds. Arsenic and its compounds are used as pesticides, herbicides, insecticides and in various alloys. Arsenic is made on an industrial scale by heating appropriate minerals in the 4 absence of air. The arsenic is condensed out as a solid. FeAsS (700°C) → FeS + As(g) → As(s) Upon heating arsenic sublimes (transfers from the solid to the gaseous state, 5 without passing through the liquid state). You may be exposed to arsenic by: Taking in small amounts in food, water or air / 6 Burning smoke from arsenic-treated wood / Living in an area with high levels of arsenic in rock / Working in a job where arsenic is made or used Exposure to arsenic can cause many health problems. Being exposed to low levels 7 for a long time can change the color of your skin. Exposure to high levels of arsenic can cause death. .