Introduction+Yazan

=Argon= == A picture of argon, but mercury is giving it the blue glow because argon is a colorless gas =Argon is one of the 7 elements in group 18= =on the periodical table called noble gases. The= =noble gases consist of helium, neon, argon,= =krypton, xenon, radon, and ununoctium and they= =are very stable. In 1785 Cavendish (an English= =physicist and chemist) performed experiments= =with oxygen and mixed air and he encountered= =argon but only thought that he had made an error.= =After nearly 100 years Lord Rayleigh found that the= =nitrogen in air was denser that the nitrogen in= =compounds, and there must be a heavier inert= =substance in the atmosphere. Repeating the= =experiments done by Cavendish with the= =assistance of William Ramsey, he found an unknown= =spectrum and called it Argon, which is Greek for= ="inactive", due to its chemical inactivity.= =Argon's appearance is as a colorless/odorless gas.= =Argon is a non-metal.=

=**Facts about Argon**=

Symbol: Ar Atomic Number: 18 Atomic Mass: 39.95 amu Melting Point: -189.3 Celsius -83.85 Kelvin Boiling Point: -186 Celsius -87.15 Kelvin Crystal Structure: Cubic Color: Colorless**
 * Name: Argon
 * Number of protons/electrons: 18**
 * Number of neutrons: 22**