The last element to be discovered in nature, rather than synthesized, was discovered In 1939. What was it?
Period 7 element elements of the 7th period. Francium is a chemical element with symbol Fr and atomic number 87. It was formerly known as eka-caesium and actinium K. It is one of the two least electronegative elements, the other being caesium. Francium is a highly radioactive metal that decays into astatine, radium, and radon. As an alkali metal, it has one valence electron. Francium was discovered by Marguerite Perey in France (from which the element takes its name) in 1939. It was the last element discovered in nature, rather than by synthesis. Outside the laboratory, francium is extremely rare, with trace amounts
Discovered attack Discovered attack In chess, a discovered attack is an attack revealed when one piece moves out of the way of another. Discovered attacks can be extremely powerful, as the piece moved can make a threat independently of the piece it reveals. Like many chess tactics, they succeed because the opponent is unable to meet two threats at once. While typically the consequence of a discovered attack is the gain of , they do not have to do this to be effective; the tactic can be used merely to gain a tempo. If the discovered attack is a check, it is