Period 3 element pulmonary agent in chemical warfare; however, chlorine is necessary to most forms of life, including humans, in form of chloride ions. Argon has no biological role. Like any gas besides oxygen, argon is an asphyxiant. Period 3 element A period 3 element is one of the chemical elements in the third row (or period) of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when the periodic table skips a row and
History of the periodic table were "earth", "water", "air" and "fire". Similar ideas about these four elements also existed in other ancient traditions, such as Indian philosophy. The history of the periodic table is also a history of the discovery of the chemical elements. The first person in history to discover a new element was Hennig Brand, a bankrupt German merchant. Brand tried to discover the Philosopher's Stone — a mythical object that was supposed to turn inexpensive base metals into gold. In 1669 (or later), his experiments with distilled human urine resulted in the production of a glowing white substance, which he called "cold